Chapter 16: flower gardening.
KEY TERMSannual bedding plant biennial border deadheading floriculture forcing island bed monocarp perennial
The modern American garden is replete with improved cultivars of hundreds of flower species, many of which have been developed just in the past 5 to 15 years. Development is ongoing in many species, and improved new cultivars are available each year. That is great news for flower gardeners, because selection is almost limitless, from the sweet alyssum to the colorful zinnia, from the blues of forget-me-nots and greens of bells of Ireland to the flaming reds of scarlet salvia and purple New England asters, to the sunny yellows and oranges of marigolds and African daisies. Colors, shapes, and sizes, seasons of bloom, and variegated foliage, all are available in bountiful variety to suit the tastes and garden designs of all (Figs. 16-1 and 16-2).
The science and practice of cultivating flowers is floriculture, and those who specialize in flower production are called floriculturists. Flower breeders and seed companies are largely responsible for the multitude of choices available to flower gardeners. As a greenhouse crop, garden flowers are grouped into the category of bedding plants, and, as such, represent the largest segment of greenhouse-produced crops (Figs. 16-3 to 16-5). Flower seed production operates on an international scale (see box).
Flowers provide color, texture, fragrance, and even motion. They are the harbingers of spring yet remain through fall, with hardy chrysanthemums, and even into winter, with ornamental cabbage, or kale (Fig. 16-6, see page 383). And what would Christmas be without the popular poinsettia (Fig. 16-7, see page 383) (see box, page 384) or Valentine's Day without roses? Flowers not only beautify our world, they provide emotional uplift and are used to celebrate birthdays and holidays, to console in times of loss and difficulty, and to express love and friendship.
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SITE SELECTION
Fortunately for flower gardeners, flower beds can occupy a diverse range of areas. Important considerations are the same as those for growing any other plants: what is the exposure and what is the soil like? There are flowering plants that work well on sloped areas, in deep shade, in full sun, and in hot and dry as well as cool and moist areas (Fig. 16-8). Some of the herbaceous plants that may be incorporated in areas with flowers--or in place of them--include ornamental grasses, ferns, and even mosses.
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When selecting the site for a flower garden, be mindful of planting under trees. This practice often leads to detrimental effects on the tree, even leading to tree death. The problem arises when rototilling in preparation for planting kills surface roots of the tree. Some trees are shallow rooters or produce many feeder roots close to the surface. Before planting, be sure the tree you want to plant under will not be damaged in this way, or you may be very sorry later. If you must plant flowers under a tree, dig individual holes for the plants and keep the planting to a minimum. Alternatively, you may plant a tree in a mixed border, and, while it is still small, plant perennial flowers around it. If you plant far enough away from the tree to avoid digging roots, then the flowers will become established by the time the tree roots grow into that area. This could be a safe way to establish a groundcover under the tree before the chance of disturbing the root system is a problem. You could establish English ivy, wintercreeper, or vinca in this way.
If you use flowering plants under the tree, be sure to consider the sun and shade requirements of the flowers first and consider how long the tree will require to reach mature size and whether shade from the tree will eventually exceed the desired amount. Keep in mind, too, that flower gardening can be a continual process that is never really finished. Therefore, you may be able to grow sun-loving perennials in that location for a few years until the tree is established and then remove them as they become shaded out. During the first few years you may begin to establish a perennial groundcover that will eventually fill in the entire area.
EXPOSURE
Flowers are categorized according to the amount of sunlight they require on a daily basis. Full sun is 6 or more hours of direct sun each day. Partial sun/partial shade is 3 to 6 hours of sun per day, and shade is less than 3 hours of sun per day. Many flowering plants prefer full sun, and, as a matter of fact, these plants represent the largest group of garden flowers. For those that will tolerate some shade, it may mean a delay in flowering or fewer or even smaller flowers. There are plants that require shade, though, and, if exposed to sun, they may exhibit leaf scorch. Some shade-loving plants do fine in direct sun for a few hours each day, and some will do better in full sun if the soil is kept moist or if temperatures remain cool. Shade-loving plants have often evolved in cool, moist, shady areas. These plants will not do well in a dry, shady location unless special remedies are applied, such as moisture-retention strategies. Even then, if temperatures are too hot, some shade-loving plants will suffer. Be mindful of the shade on your site, as some shade is quite dense rather than dappled, and such areas should only be planted with the most shade-loving species available.
The plants in our gardens have originated from places all over North America and the world. The more you can learn about the soil and climate conditions in a plant's place of origin, the better able you will be to make a decision about whether to use it in your garden, and, if so, in what location it will grow best. Table 16-1 provides a listing of plants for special situations found in the landscape.
SOIL
Flowering plants typically require well-drained, neutral soil. However, plants that have evolved in arid regions of the West often prefer alkaline soil. Those that evolved in shady areas often prefer moist soil that is slightly acid.
If the soil is poorly draining, it is advisable to use raised beds. Raised beds have several advantages: they raise the height of the flower bed for better viewing; they improve drainage, and they allow the soil to warm up better than flat areas. Raised beds may be made simply of mounded soil, or they may consist of structures built with cinder blocks, landscape timbers, or even boards. If you find it necessary to use raised beds, bring in topsoil and amend it with compost, aged manure, peat moss, grass clippings, or other organic materials. Clay soils and sandy soils should both be amended with organic matter to improve structure, aeration, and drainage.
PREPARING THE GROUND
Soil preparation for a flower bed is similar to that for a vegetable garden (see chapter 13). The area should be cleared of existing vegetation, turf, and weeds. A pre-emergent herbicide may be applied if transplants are going to be used. It is not necessarily advisable to lay landscape fabric down if you wish the flowers to spread and fill in an area, as the fabric will deter or even prevent this from happening. Also, it is very difficult to grow annuals in a bed covered with landscape fabric because of the close spacing required for filling in an area. You may begin soil preparation in the fall by applying a nonselective herbicide over the area to rid it of plants.
You may use an alternative to killing everything with an herbicide. The following methods have been used with success: the layer method, the solarization method, and newspapers. These methods are described in chapters 5 and 10.
Any soil that you plant into should be adjusted for pH as necessary, as determined by a soil test before planting. Fertilizer may be worked into the soil before planting, as well, if soil test results indicate that it is needed. General purpose balanced fertilizer (13-13-13 or 15-15-15) is recommended.
PLANT SELECTION
There are several qualities of plants that you need to be familiar with during the plant selection process. The wrong plant in the wrong place results in wasted time and effort, wasted money, and poor garden design. There are many reference materials you can check to find the requirements for a particular plant. You can also read labels on plants that are sold at your nursery or garden center. Read books on garden design and flower beds before you get started. If you have never grown flowers before, you may want to copy something you have seen in someone else's yard or in a book. There are even preplanned flower bed designs readily available at no charge at many nurseries and garden centers. As you become more experienced, you may want to experiment with your own ideas. A good rule of thumb is to work with your site and seek flowers that will perform well in the conditions you can easily provide rather than going to Herculean efforts to change your site to suit the species you decide to grow. Another good rule of thumb is to combine plants with similar requirements. The site will usually determine this, whether it is moist and shady, or dry and alkaline, and so on.
Good flower bed design incorporates some basic design principles, such as color, texture, plant size, and plant shape. Keep these in mind as you plan your garden and you will have a satisfying and appealing design. These principles are discussed in more detail below.
PLANT HABIT
Annuals
Annuals are plants that complete their life cycle in 1 year. Seeds are planted, the plant grows, flowers, set seed, and dies. Many annuals do not even last a full year, but complete this life cycle in as little as 1 month. Most garden annuals last for a full growing season and die when temperatures become too cold.
Annuals are used in flower beds for their color. Many annuals have relatively large, showy flowers that last for long periods of time. Many favorite annuals will bloom throughout the growing season. They are used as border plants either alone or in combination with perennials and even trees and shrubs (Fig. 16-9).
There are warm-season and cold-season annuals, but the bulk of flowering annuals are warm-season plants (Table 16-2). These should be started by seed indoors about 6 weeks before the last frost and planted outside as soon as the danger of frost has passed. You may purchase transplants of a wide variety of annuals. Herbaceous flowers and particularly annuals comprise a large part of the category of plants known as bedding plants, representing the largest segment of greenhouse production. Cool-season plants grow and bloom well in late winter to early spring and fall to early winter, depending on local temperatures. They generally do not do well in the heat of summer and may go dormant or die.
Perennials
Perennials are plants that come back every year. There are woody and herbaceous perennials. Woody perennials include trees, shrubs, some vines, and groundcovers. Herbaceous perennials include many flowers and ornamental grasses. Flowering herbaceous perennial plants may be started from seed but do not always bloom in the first year. However, after the above-ground portion dies back in winter, new growth emerges in spring as temperatures warm and days lengthen. They will then bloom in their second year and set seed. Although this completes the biological life cycle and the above-ground portions die back every winter, new growth emerges every spring (Fig. 16-10). Some perennials are short-lived and may only regrow for 3 or 4 years. However, many will continue to regrow for many years. Each year their root mass increases to the extent that they can crowd out other plants in the bed. Then it is necessary to divide the crown to reduce plant size. Perennials that are overly aggressive in this way are labeled invasive. Some perennials are also invasive because they set a lot of seed, and the seeds germinate readily. Such plants seem to pop up all over the garden and even in other beds.
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Each year the Perennial Plant Association designates a Perennial Plant of the Year. The most important criterion is good performance in various geographic locations grown under varying climatic conditions. Some winners include Japanese painted fern (Athyrium niponicum 'Pictum'), Phlox 'David' Paniculata Group, and lenten rose (Helleborus x hybridus). 'Becky' Shasta daisy (Leucanthemum 'Becky') won because of its bright white flowers, sturdy stems that resist lodging, and long season of bloom, in addition to its great performance across the country.
In the garden, perennials are used for color and texture. They often provide more height and fullness than many annuals. Perennials bloom over varied periods of time. Some bloom all summer long from late spring until frost, whereas other bloom for a 2- to 4-week period only. Table 16-3 shows the bloom seasons for select perennials.
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Biennials and Monocarps
In addition to the life cycles represented by annuals and perennials, there are two other types of life cycles flowering plants exhibit. Biennials require two seasons of growth to complete their life cycle. In the first season the seed germinates and grows only vegetatively, and then the above-ground portion of the plant dies back during winter. The following season shoots emerge, the plant grows and blooms, sets seed, and dies. Foxglove is a biennial. Monocarps live for several to many years, growing vegetatively. When they eventually mature, they bloom and set seed, and then the entire plant dies.
Ornamental Grasses
Ornamental grasses work well in a mix of grasses or to complement the perennial border. They offer textures beyond the range available from flowers alone. One attraction of ornamental grasses is the aesthetics they provide in fall and throughout winter. By allowing the foliage to dry down and remain in place, they provide beiges and tans in fall and add winter interest to the landscape. Ornamental grasses often add a touch of elegance to the winter garden when they are covered with ice or snow. They add a variety of color other than green to your summer garden also. From the green-blues of blue fescue to the white and yellow variegation of maiden grass, ribbon grass, and others, ornamental grasses bring a palette of colors to the perennial border. They range in size from 6 inches to more than 9 feet tall. Some are upright and spreading, whereas others are clump-forming with a mounded shape (Fig. 16-11, see page 396).
Ornamental grasses generally require full sun for best performance; however, there are some that tolerate or require shade (Table 16-4, see page 397). Some ornamental grasses can be invasive, so familiarize yourself with the details of a grass before adding it to your garden. If you desire a plant that will take over a low-maintenance area, then an ornamental grass may be your remedy.
Bulbs
Chapter 2 presents a discussion of specialized organs on flowering plants. These include true bulbs, corms, rhizomes, tubers, and tuberous roots. Many of the plants grown from specialized plant organs bloom in spring before trees have leafed out. These include tulips, daffodils, crocuses, anemones, and snowdrops (Fig. 16-12). Such plants benefit from nearly full sun because of the lack of leaves. Other plants may not bloom until late spring to late fall, and most of them require full sun. They will not perform well in the shade under trees or elsewhere. Alliums, dahlias, gladiolus, iris, and Asiatic and Oriental lilies all bloom in late spring to summer. Autumn crocus and resurrection lily bloom in late summer to early fall. The earliest blooming bulb plants are snowdrops and crocuses. Table 16-5 (see page 399) lists common bulbs and other specialized plant organs.
Bulbs that are planted in the fall usually require a cold treatment for complete flower development. In the South and areas of the West, such bulbs may require a cold treatment before planting. This is similar to forcing of bulbs to get them to bloom indoors in late winter and early spring (see chapter 12 for details on how to force bulbs).
Ferns
Ferns provide a lush appearance with their leafy foliage (Fig. 16-13, see page 402). Botanically, ferns are not flowering plants but rather are pteridophytes. They often work quite well in shady moist locations; however, some ferns tolerate drier conditions and even partial sun (Fig. 16-14, see page 402). The latter include Athyrium and Osmunda species and cultivars. Ferns may be evergreen in warmer climates, but work quite well as perennials in temperate climates where they are hardy (Table 16-6, see page 403). Ferns may be used in combination with one another and also work well with other foliage plants, such as hostas. They can be used quite successfully as a groundcover. Once established, some ferns will fill in a space and benefit from crown division every 3 years.
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Vines
Vines may be herbaceous or woody, and the herbaceous ones may be annual or perennial. Plants that grow as a vine are useful in covering vertical surfaces. Vertical surfaces covered with a vine or liana can substitute for a wall while providing interest, and vines take up less space than a hedge or shrub screen. Vines may be used for their showy flowers, such as morning glory and clematis, or they may be used for their foliage, such as English ivy and wintercreeper (Fig. 16-15, see page 404). The latter are commonly used as a groundcover, but they can grow vertically if they are provided the proper surface. Wisteria grows as a liana and is often used to cover pergolas, providing shade for a seating area, as well as showy flowers in spring. Vines have a variety of ways for attaching themselves to walls or posts. One way is suction cups, a second way is twining, and a third way is by tendrils. Table 16-7 (see page 405) lists popular vines and their hardiness and habit.
For a touch of spring in your house, you can also bring in branches from your favorite spring-blooming trees or shrubs to bloom indoors (see box, page 406).
GARDEN DESIGN
Designing a garden requires an integration of several different factors, notably, color, texture, and height. However, these are only basic considerations; another consideration is whether you want to use annuals or perennials alone or in a mix. In addition to what goes in a garden, you should consider the surroundings as well: will the garden be surrounded by a sea of green turf, criss-crossed with informal stepping stones, or bordered by a low wall? Bringing all these components together leads one into garden design and landscaping. Themes are often central to good garden design. Some theme gardens pictured here include a desert garden, a rose garden, and a prairie garden (Figs. 16-16 through 16-18, see pages 406-407). Garden design has been influenced by designers with specific ideas about what kinds of plants belong in a garden and specific ways to use plants. Their ideas are influenced by aesthetics as well as concern for--or lack of concern for--whether plants should be native to be included in a good garden design. Two of the many notable garden designers include Gertrude Jekyll and Jens Jensen (see boxes, page 408). Other ideas include cottage gardens, period gardens, and cut-flower gardens.
Color in Garden Design
Color is really what flowers are all about. Bright colors attract attention and for many that is why flower beds are so rewarding. But the artistic eye recognizes that color combinations can be aesthetic or chaotic. For eye-pleasing color combinations, the rules for color mixing are similar to those in art. Garden designers can use the color wheel to mix and match flower colors (Fig. 16-19, see page 409). Colors adjacent on the wheel blend harmonically, whereas those opposite each other on the wheel are highly contrasting. Both combinations can be useful in garden design. Gertrude Jekyll, the pioneer of the modern perennial border, said, "a bed of blue flowers can be absolutely ruined by the lack of yellow" (see box, page 408). A color scheme with three colors works well, especially when two are harmonic and the other is contrasting. Two examples are purple, blue, and orange and lime green, yellow, and pink.
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Colors can be broken into two groups: cool colors and warm colors. Cool colors include red, blue, and purple. They tend to recede and fade, especially when viewed from a distance. Warm colors include red, orange, and yellow. Notice that red is in both groups. That is because there are cool reds and warm reds. Green foliage is generally used as a neutral, background color. But do not overlook the off-greens, such as the silvery green of Dusty Miller. Silver, blue, and white are attractive together. Yellow-green is a warm color, and blue-green is a cool color.
Pay attention to white. It is sometimes creamy and other times pure. Creamy white goes well with yellow and orange, whereas pure white looks good with blue, red, and purple. As a matter of fact, many colors can have tinges of adjacent colors on the wheel. For example, blues may be greenish or purplish, purples may be more bluish or reddish, and reds may be bluish or orangeish. The variations away from the pure color will affect how well the colors combine--or how much they clash--with other colors. Shades of colors are achieved in painting by adding black. This creates a more earthy shade. Shades of colors exist in flowers as well. Tints are achieved by adding white. This leads to pale and pastel colors. As in art, combining shades or tints is more pleasing to the eye than mixing them together.
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Some flowers come tantalizingly close to black, although they are usually a very dark burgundy or purple. Some examples of black flowers are pansy 'Accord Black Beauty,' trillium 'Eco Black Magic,' bearded iris 'Superstition,' clematis 'Romantika,' dahlia 'Arabian Night,' and daylily 'Starling.' The ornamental sweet potato cultivars, 'Ace of Spades,' 'Black Heart,' and 'Blackie,' provide dark purple to black foliage, as does 'Nigrescens' black-leaved lily turf. In Table 16-8 (see page 410) many common garden plants are grouped into color categories.
Texture in Garden Design
Large, bold leaves and tiny, delicate leaves represent the extremes of leaf texture: course and fine. Bold leaves should be used with caution, as they can dominate a scene and overpower plants that are less bold. Bold foliage is often associated with a tropical feel and can impart one. Tropical plants such as canna lilies (Canna spp.) elephant ear (Colocasia spp.), and Bird-of-paradise (Strelitzia reginae) can be used to achieve such a desired look. On the other hand, fine-textured ferns (Adiantum spp.) or forget-me-nots (Myosotis spp.) can get lost in the presence of other, bolder species. Many species are fairly neutral with respect to texture and combine well with either bold- or fine-leaved species. Texture is perhaps the most difficult aspect of flower garden design to really master. Observe other gardens with a critical eye to texture, and you will soon learn what is appealing and what is simply garish, confusing, or ineffectual.
Height in Garden Design
Annuals range in height from a few inches to a few feet or more, in the case of sunflowers that may grow taller than 10 feet. Tables 16-9 and 16-10 (see pages 413 and 415) provide heights of annual and perennial flowers. Height is an important consideration when deciding the type of bed to make. There are two basic types of beds: those that are to be viewed primarily from one side, and those that are to be viewed from all sides. When beds are to be viewed primarily from one side, they are referred to as borders (Fig. 16-20, see page 417), and when they are to be viewed from all sides, they are island beds. Borders may have a backdrop, such as a wall or fence, but this is not necessary. For example, borders may be used with a driveway or sidewalk. Some borders are built up on berms to increase their visibility and are often done this way to visually separate two areas. Island beds may be round or rectangular or just about any shape. In an island bed, tall plants are placed in the center of the bed, with plants in decreasing size as you come to the perimeter of the bed. With borders, tall plants are in back, with increasingly shorter plants in the front. Although these ideas seem obvious, if the height of the plants is overlooked during the design stage, the result will be wasted time and money or the need to rearrange plants.
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FLOWER BED MAINTENANCE
As many garden designers know, a flower bed will not maintain its beauty and form without regular maintenance. Some plants fail to thrive for more than a few years, whereas others become invasive. Still others are introduced into the bed by birds, wind, squirrels, or other means. Therefore, weed control, pruning, division of overgrown plants, and other maintenance techniques must be practiced to keep the flower bed looking its most aesthetic.
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Weed Control
Flower beds that are well mulched should have very little incidence of weeds in them. But the mulching process is ongoing, and mulch must be maintained at a certain depth, usually about 4 inches, to ensure that weed seeds lying dormant in the soil do not receive adequate light for germination. Unfortunately, birds and wind can deposit weed seeds on top of mulch. The germinated seeds may not develop deep roots, especially if a landscape fabric is installed first, but, nevertheless, they can become quite extensive. Some tree species set prolific amounts of seeds, and germination rates are remarkably high. Squirrels often bury seeds in flower beds, too. Consistent and regular monitoring is important, as is regular removal. If mulch alone does not do an adequate job of preventing weeds, then a fabric landscape barrier may be a suitable alternative. These are porous materials that allow water to flow through. When landscape fabric is used, only 2 inches of mulch are required.
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Plants should be placed as close together as possible to crowd out potential weeds. Be careful with herbicides in flower beds. Some herbicides will harm your flowers, even if they do not contact the foliage directly. Examples include herbicides that have residual activity in the soil or those that can move through the soil, especially if the flower bed is sloped. Other examples are herbicides that volatilize to produce vapors that can harm your desirable plants. You should only use a preemergent herbicide on a flower bed if you know for certain you will not be planting flower seeds there in the following months. Selective herbicides that kill grasses may also be harmful to your monocot garden plants such as lilies, daylilies and hostas, in addition to ornamental grasses.
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Deer and the Garden
See chapters 8 and 9 for a more thorough discussion of diseases and pests. Weed management is discussed in chapter 10.
Deer can be a problem in your garden. They seemingly eat everything in sight, although they do have their favorites. There is no guaranteed method for keeping deer out of the suburban or country garden, but there are some plants that they prefer not to eat. Some of these are listed in Table 16-11 (see page 418). Try to avoid plants they really like, and plant more of what they prefer to avoid.
Putting the Garden to Bed
In the fall, after frost in temperate regions, is the time to perform some flower bed maintenance activities. Autumn is an ideal time to apply mulch in the form of wood chips or shredded leaves. Wait until after a few frosts have occurred to reduce the incidence of small rodents taking cover in the garden when cold weather sets in. The mulch will help reduce frost-heaving in the flower beds during winter.
It may be desirable to remove spent flower heads, but one should consider their aesthetics in winter. Many plant species have quite attractive seed heads that remain on the plant, often throughout the winter. In addition to their natural beauty, developing seed heads can provide food for a variety of birds. Flower foliage also provides a safe haven for over-wintering or pupating butterflies. Ornamental grasses can be quite useful for their aesthetic appeal throughout winter. If you do remove spent flower heads, be sure to add them to the compost pile so that you can eventually return the nutrients to the garden bed. Consider leaving spent foliage in the garden bed, too, for it can decompose in place to some extent during winter without detracting from the appearance of the bed, especially if snow cover is common in your location. Removal of last year's growth can be performed in spring just before new growth begins to appear.
If disease has been a problem, spent foliage should be removed. Other cases for which foliage clean-up is necessary include unsightly beds, rotting plant material, or plants that have fallen into a pathway, driveway, or other area outside the flower bed. Tall stems that have a tendency to fall apart from the center of a clump or simply to fall over should be cut back before winter when the weight of snow or ice would render them even more unsightly. Plants that serve as over-wintering hosts for garden pests should also be removed. When cutting plants back, leave 2 to 3 inches above the ground so as not to damage buds at the crown that will provide next year's growth.
Moving Plants Around
There are a variety of reasons that it might be desirable to move perennials from their current location. Perhaps they have outgrown their space and require dividing. Or perhaps they once occupied a sunny spot near a shade tree that has since grown to cast too much shade for healthy growth or flowering. Sometimes, perennials need to be moved because of redesign of a bed or even remodeling of a home. Fortunately for the perennial gardener, perennials can be moved with a little effort and planning. Ideally, perennials should be moved at the same time of year they can be divided. Summer- and autumn-flowering plants can be moved in spring. Plants with woody roots or taproots should be divided when they are dormant, but the ground is not frozen. Plants should be kept shaded and their root balls intact during moving.
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Prepare the planting hole before digging up the plant, and water-in well after moving it. Make a small berm around the plant that will hold water for the first few days. Then break down the berm after the plant appears to be growing-in. If you want to thin out a plant that is overgrown in its current place, you can dig into the crown of the plant and remove a section. The remaining plant will fill in the area, and the section you have removed can be safely moved to a new location. It will survive as long as you have included some root and some shoot material. Before planting, remove any plant tissue that has become separated, such as parts of leaves or roots. Place the new plant in the hole, make a berm, and water-in as described before.
Fertilizing
Pre-planting fertilizer applications should be based on soil tests. If organic matter or amendments are adequate, no additional fertilizer may be necessary. Organic or inorganic fertilizers may be used, if soil tests determine a need. For plants that grow better in an acid environment, addition of organic matter can achieve the two goals of lowering pH while adding nutrients to the soil. Starter fertilizers are added during planting. These can be worked into the soil surrounding the plant or added to the irrigation water and applied when watering-in.
Most perennials will bloom in response to a combination of factors, including the age of the plant and photoperiod. However, special fertilizer with an elevated level of phosphorus may be applied to encourage blooming. These fertilizers are readily available and are usually sold as bloom fertilizer.
Pruning Perennials
Deadheading is the removal of flowers after they have finished blooming. Removing them sometimes results in formation of new flowers. This is thought to be due to a response in flowering plants to produce offspring. In a sense, it tricks them into forming additional flowers after already having produced some. There is possibly another explanation for this phenomenon. It may be that the plant has enough resources either to produce more flowers or to develop seeds. It is known that seed production requires a lot of carbohydrates and energy. By removing flower heads before plants put those resources into seed production, more flower production is possible.
Pruning perennials is a matter different from deadheading, although the desired results are also increased flowering. Not all perennials will respond favorably to pruning (Table 16-12). For those that do, the largest increase in flowering is obtained with the earliest pruning. The later pruning is performed, the closer the plant already is to producing flowers, and the less the effect achieved.
Division
Because their root systems increase from year to year, many herbaceous perennials and most ornamental grasses tend to have an increasing number of shoots each year. Within a matter of a few years, they fill in an area and may even outgrow the spot they are in. When that happens, you may dig them up and divide them into smaller clumps. This technique is explained in chapter 4. Division can be performed on plants whenever they are bigger than you want them to be. It can be done at any time, but the best time is early spring before they get too large to handle. Planting the divisions at this time will allow the greatest period of growth before frost, allowing the new plants to become established.
SUMMARY
Flowers provide beauty and often fragrance to the home landscape. They are typically grown in beds or containers in full sun to full shade. Flower plantings can be designed to include blooms throughout the growing season using both cool and warm season plants in temperate climates. Annuals, perennials, biennials and monocarps, ornamental grasses, and bulbs provide a full palette across the seasons and in the different areas of the yard. Ferns add luxuriant foliage, whereas vines can provide groundcover or cover a vertical space. Flower heights, shapes, colors, and textures all add to the aesthetics in the flower garden. The use of a color scheme can add a sense of design aesthetics, whereas garden styles vary according to taste, historical influence, and creative talent.
Routine maintenance for flower gardening includes fertilizing, deadheading, fall clean-up, weed and pest management, and division of perennials. Flower gardening can be low or high maintenance, depending on the preferences of the gardener. For the best results, select appropriate plants, plan for weed management in advance, and plan for regular tending of the garden to minimize the tasks involved. With these criteria in mind, flower gardening can be the most creative and fun type of gardening to do.
HANDS-ON ACTIVITIES
* Design a flower bed using a color scheme or to provide color throughout the growing season.
* Design three different types of flower beds using different themes, e.g., Colonial America, English cottage garden, American prairie, desert natives, woodland shade garden, alpine rock garden, and children's garden. Investigate the appropriate species and colors.
* Write an essay or present a talk about some period of time and the flower-gardening practices used.
REVIEW QUESTIONS
1. Those who specialize in flower production are called--.
2. Which region did impatiens originate in?
3. Explain the effects of rototilling under trees to make flower beds.
4. Full sun means how many hours per day of full sun? Partial shade/sun? Shade?
5. List two advantages of growing flowers in raised beds.
6. Distinguish between warm- and cool-season annuals.
7. Compare and contrast the life cycles of annuals and perennials.
8. Compare and contrast the practices of pruning perennials and deadheading them.
9. What are the qualities of warm colors? Cool colors?
10. Compare and contrast beds and borders.
SELECTED REFERENCES
Austin. S. (1990). Color in garden design. Newtown, CT: Taunton Press.
Bisgrove, R. (1992). The gardens of Gertrude Jekyll. Berkeley, CA: University of California Press.
The Clearing Folk School. Retrieved October 3, 2005, from http://www.theclearing.org.
Noland, D., & Bolin, K. (2000). Perennials for the landscape. Danville, IL: Interstate.
Phillips, E., & Burrell, C. C. (2004). Rodale's illustrated encyclopedia of perennials. Emmaus, PA: Rodale.
Roth, S. A. (1995). Better Homes and Gardens complete guide to flower gardening. Des Moines, IA: Meredith Books.
Sunset Books and Sunset Magazine. (Eds.). (1997). Sunset national garden book. Menlo Park, CA: Sunset Books.
Richard Craig and Claude Hope: Leaders in Flower Breeding
Dr. Richard Craig
Geraniums (Pelargonium x hortorum) are one of the top five bedding plants in the United States, and they have been for many years. But what many people today do not realize is that in the early 1960s the use of geraniums as a bedding plant was failing because of transmission of bacterial blight (Xanthomonas) during vegetative propagation. Growers lost entire geranium crops, representing a monetary loss of significant proportions. Simply put, geraniums were on their way out of greenhouse production.
However, and not a moment too late, in 1963 Dr. Richard Craig made a lasting contribution to the floriculture and bedding plant industry when he introduced the first seed-propagated geranium, 'Nittany Lion Red,' with professor of plant breeding Darrell Walker. This remarkable accomplishment stimulated the commercial development of hundreds of improved geranium cultivars. Since then, Craig, often with the help of students in his plant-breeding program at the Pennsylvania State University, has developed 24 patented cultivars of geraniums and regal pelargoniums. He has also been awarded a process patent for the year-round production of regal pelargoniums.
Craig describes his work as "creating a more beautiful world," which he has done by "developing new flowers and motivating students." He taught horticulture classes at Penn State for 40 years, supervised 40 graduate students, and directed more than 200 undergraduate research projects. One of the leading discoveries made in his research program was the existence of pest resistance in the garden geranium. Through years of study, Craig's team eventually unraveled the molecular, morphological, and genetic mystery of this pest resistance and actually isolated and cloned a gene that codes for the pest resistance enzyme.
Craig has received many honors throughout his career, including a Bronze Medal for Research for outstanding contributions to the genetics of African violets, Fellow of the American Society for Horticultural Science, the Alex Laurie Award for Floricultural Research, and the American Horticulture Society's Luther Burbank Award. He was inducted into the Society of American Florists' Floricultural Hall of Fame in 1991.
Claude Hope
Claude Hope has been called the 20th century's most important flower breeder. Why is that? His great plant breeding accomplishment was to bring the humble yet ubiquitous shade-loving impatiens (Impatiens wallerana) to the forefront of bedding plant production. Another moniker he has been given is "the father of the impatiens." It was not easy--many years of traditional plant breeding eventually led to the breakthrough development of the Elfin series in 1968. These new cultivars were free-flowering plants with a compact habit that came in eight colors.
Although Hope conducted his project in Costa Rica, the flower originated in East Africa and was called Sultana for the sultan of Zanzibar. But when Hope was stationed in Costa Rica during World War II to run a quinine production facility, he saw the little flower growing along roadsides and in gardens and coming up through cracks in sidewalks. He thought there was potential in the plant because he observed them "in all colors except white and purple" with sizes ranging from a few inches to a few feet tall. He established a farm, Linda Vista, in Dulce Nombre, and a company, Pan-American Seed Company, to conduct his work and sell his product. Nowadays, impatiens are one of the top five bedding plants, and one of the very few annuals that tolerate as much shade as you have. They thrive in shady, moist conditions, and offer many bright colors to any shady garden spot: 15 solid colors, white star patterns, and picotee bicolors. Linda Vista covers 400 acres today and produces a majority of the world's hand-pollinated [F.sub.1]-hybrid impatiens seeds.
Made in Mexico: The Poinsettia
How did the ever-popular poinsettia become so strongly associated with Christmas in the United States? To understand this, one must first understand where the poinsettia came from. In the 1820s President Andrew Jackson sent Joel Poinsett to Mexico to serve as our first ambassador to that country. Poinsett had a great interest in plants and introduced the American elm to Mexico while he served there. He also searched the land for interesting new plants. In 1828 he discovered the red poinsettia growing alongside the road. What many take as the large red petals of the flowers are actually bracts, or modified leaves. The flowers are enclosed in tiny yellow structures located at the center of the colorful bracts. The floral structures are called cyathia. Poinsettias are a short-day plant, and their wintertime blooming makes them a natural for Christmas traditions. This is true not only in the United States but also in Mexico and Central American countries. Its natural habit is to become woody and grow like a large shrub to small tree. To get the poinsettia plant to grow and bloom in a small pot, rooted cuttings are grown from larger stock plants. A combination of plant growth hormones and pinching may be used to keep the plants small and encourage branching for a full, bushy plant. Flowers are initiated by exposure to short days. Much genetic work has been done with poinsettias so that nowadays, in addition to the traditional red color, various shades of pink and creamy white and various forms of speckled and spotted cultivars are available. The Ecke Ranch in southern California grows most of the poinsettias sold throughout the United States.
Forcing Woody Flowering Branches
If you want to bring spring indoors, one way to do this is to simply bring your favorite spring-blooming trees and shrubs inside. Of course, you cannot move entire trees or shrubs indoors, only to move them back out again in summer. But you can bring in branches a week or more earlier than they would normally bloom outside and enjoy their blooms inside. This is possible because the flower buds have already received their winter chilling during the winter. The technique is similar to forcing, except it is not necessary to provide the cold temperature treatment as you need to do when forcing bulbs indoors. Some flowering woody plants that respond well to this treatment are forsythia, crabapple, star magnolia, peach, flowering almond, cherry, pear, plum, and quince. When these woody plants are placed into a container of water, it is necessary to re-cut the stems under water.
Gertrude Jekyll: Garden Designer for Our Time
Gertrude Jekyll lived from 1843 to 1932, so how could she be called a garden designer for our time? Many of her ideas can be readily seen in the modern perennial garden and in the use of arbors and pergolas. The ideas of Jekyll work well in American landscape design for at least one reason: the somewhat informal nature of perennial borders and beds. This semi-informality is popular in American culture and complements the use of native species in the garden. Ms. Jekyll was a master of combining color, texture, and form.
Gertrude Jekyll wrote about her gardening and landscaping ideas in Country Life, The Garden, and Gardening Illustrated. She also wrote 13 books. She collaborated with the architect Sir Edwin Lutyens by designing gardens for many estates he designed. They worked closely together, as they shared ideals about beauty and design. She ran a garden center. She was also a plant breeder in her own right and developed many new cultivars of plants.
Jens Jensen: Prairie Style
Jens Jensen was a Swedish immigrant who came to America in 1884, at age 4. He spent much of his adult life in Chicago, Illinois, and Wisconsin. In 1886 he began working for the Chicago West Parks District. Beginning at that time and continuing throughout his life, he studied the native plants of the area and developed his horticultural skills. He was a lover of nature and enjoyed the out-of-doors, and he came to abhor what he perceived as rampant consumerism. He wished instead to emphasize the simple gifts of beauty that are available to all, regardless of income level. He was influential in establishing the Illinois State Parks System and the Cook County Forest Preserves. He founded Friends of Our Native Landscape with the aim of preserving important natural areas throughout the Midwest.
Some of Jensen's major contributions that can still be seen today are the Lincoln Memorial Garden in Springfield, Illinois, The Shakespeare Garden at Northwestern University in Evanston, Illinois, and the Garfield Park Conservatory in Chicago. Later in life, Jensen dreamed of establishing a high school based on the folk schools that sprung up during his youth in Sweden. He established an educational center called The Clearing in Door County, Wisconsin. His idea was to have a school where "the wilderness and the cultivated meet, so youth can be free to cultivate and nourish its inherent abilities and wisdom, free from the shackles of intellectual decay." Classes were taught in ecology, soil studies, floriculture, landscape design, drafting, and construction, entomology, sculpture, music, and architecture. Open areas and communing with nature were emphasized there, as was a love of learning. He wanted students to come there for the love of learning above all else.
Jensen wanted to bring people together with nature and believed in designing the landscape to accommodate this coming together. He wished his imprint on nature to be as natural as possible. He ultimately felt that the American garden depended on the natural forms of native American plants.
Dr. Marietta Loehrlein currently teaches horticulture classes at Western Illinois University in Macomb, Illinois. She earned both her bachelor's degree in Agronomy and her master's degree in Plant Genetics at The University of Arizona. Her master's research project was concerned with germination problems associated with triploid seeds, from which seedless watermelons grow. Following that she worked for 5 years in a breeding and research program for Sunworld, International near Bakersfield, California. She worked with peaches, nectarines, plums, apricots, and cherries. Then she returned to school to earn her Ph.D. in Horticultural Genetics at The Pennsylvania State University. Her Ph.D. research focused on flowering processes in regal pelargonium (also called Martha Washington geraniums). While at The Pennsylvania State University, she bred a new cultivar of regal pelargonium, "Camelot." At Western Illinois University, Dr. Loehrlein teaches nine courses: Greenhouse and Nursery Management, Introductory Horticulture, Landscape Design, Landscape Management, Home Horticulture, Plant Propagation, Turf Management, and two courses in Plant Identification.
TABLE 16-1
Annuals and Perennials for Special Situations
SITUATION ANNUAL
Shade Begonia, browallia, coleus, impatiens,
Forget-me-not (Myosostis sylvatica),
lobelia, pansy, periwinkle, torenia
Moist Ageratum, browallia, calendula, columbine,
flowering kale, impatiens, lobelia,
nicotiana, ornamental pepper, salvia,
stock, sweet alyssum, pansy, torenia
Dry Amaranth, African daisy, celosia, cleome,
gazania, Dusty Miller, strawflower,
zinnia, petunia, portulaca, blue salvia
SITUATION PERENNIAL
Shade Ajuga, astilbe, hosta, bleeding heart, ferns,
lungwort, Virginia bluebells
Moist Monkshood, astilbe, arisaema, goat's
beard, swamp milkweed, English
painted fern, black snakeroot, Joe Pye
weed, filipendula species, sweet
woodruff, Geum rivale, swamp
sunflower, yellow flag iris, rose
mallow, bluets, Siberian iris, blue flag
iris, Southern blue flag, mint, cardinal
flower, forget-me-not (Myosotis),
purple moor grass, bamboo
(Phyllostachys), beebalm, primula,
bloodroot, globeflower, vernonia,
calla, water forget-me-not
Dry Yarrow, lily-of-the-Nile, Agave, Aloe,
amaryllis, artemesia, false wild indigo,
butterfly milkweed, coreopsis, blue
fescue, gaillardia, bearded iris, red-hot
poker, liatris, linum, oenethera,
fountain grass, Russian sage, salvia
species, sedum, lamb's ears, Mexican
sunflower, verbena, yucca, zinnia
TABLE 16-2
Warm-Season and Cool-Season Annuals
COMMON NAME SPECIES SEASON
Ageratum Ageratum houstonianum Cool
Alyssum Lobularia maritima Cool
Amaranth Amaranthus caudatus Warm
Argyranthemum Argyranthemum Cool
Cabbage/kale, Brassica spp. Cool
ornamental
Calibrachoa Calibrachoa spp. Warm or cool
Carnation Dianthus caryophyllus Cool
Celosia Celosia argenteas Warm
Cleome, spider Cleome hasselrana Warm
flower
Cosmos Cosmos bipinnatus Warm
Cuphea Cuphea spp. Warm
Dusty Miller Senecio cineraria Warm or cool
Gaillardia Gaillardia spp. Warm
Gazania Gazania spp. Warm
Geranium Pelargonium hortorum Warm
(Pelargonium)
Globe amaranth Gomphrena globosa Warm
Gypsophila Gypsophila elegans Warm
Heliotrope Heliotrope arborescens Warm
Hollyhock Alcea rosea Warm
Impatiens Impatiens wallerana Warm
Impatiens, New Impatiens hawkeri Warm
Guinea
Lobelia Lobelia erinus Cool
Marigold Tagetes spp. Warm
Mealy-cup sage Salvia farinacea Warm
Morning glory Ipomoea purpurea Warm
Nasturtium Tropaeolum majus Warm
Nemesia Nemesia spp. Cool
Nicotiana Nicotiana spp. Warm
Pansy Viola x wittrockiana Cool
Pentas Pentas lanceolata Warm
Periwinkle Catharanthus roseus Warm
Petunia Petunia x hybrida Warm or cool
Pinks, Sweet Dianthus species Cool
William
Pot marigold Calendula officinalis Warm
Sage, scarlet Salvia spp. Warm
Snapdragon Antirrhinum major Cool
Sunflower Helianthus annuus Warm
Sweet pea Lathyrum odoratum Cool
Verbena Verbena spp. Warm
Zinnia Zinnia spp. Warm
TABLE 16-3
Bloom Times of Selected Perennials
USDA
SEASON OF HARDINESS
BLOOM COMMON NAME SPECIES ZONE
Early Basket-of-gold Aurinia saxatilis 3-7
Spring
Bethlehem sage, Pulmonaria 3-8
lungwort saccharata
Christmas rose Helleborus niger 3-9
Creeping phlox Phlox stolonifera 2-8
Cushion or spurge Euphorbia 3-9
euphorbia polychroma
Evergreen candytuft Iberis 3-9
sempervirens
Heartleaf bergenia Bergenia 3-8
cordifolia
Lenten rose Helleborus 4-9
orientalis,
Helleborus x
hybridus
Moss phlox Phlox subulata 3-9
Myrtle euphorbia Euphorbia 5-10
myrsinites
Polyantha primrose Primula x 3-8
polyantha
Purple rockcress Aubrieta 4-8
deltoidea
Wall rockcress Arabis caucasica 4-7
Late Ajuga, bugleweed Ajuga reptans 4-8
spring
Alpine aster Aster alpinus 4-9
Barren strawberry Waldsteinia 4-7
ternata
Bearded iris Iris x germanica 3-10
Bleeding heart Dicentra 3-9
spectabilis
Bloodred cranesbill, Geranium 3-8
hardy geranium sanguineum
Blue false indigo Baptisia australis 3-9
Blue stars Amsonia tabernae- 3-9
montana
Carolina lupine Thermopsis villosa 3-8
Columbine Aquilegia hybrids 3-9
Dead nettle Lamium maculatum 3-8
European wild ginger Asarum europaeum 4-7
Foam flower Tairella cordifolia 3-8
Globeflower Trollius europaeus 3-8
Green and gold, Chrysogonum 5-9
goldenstar virginianum
Jacob's ladder Polemonium 3-7
caeruleum
Lady's mantle Alchemilla mollis 4-7
Leopard's bane Doronicum orientale 4-7
Maiden pink Dianthus deltoides 4-9
Mountain bluet Centaurea montana 3-9
Oriental poppy Papaver orientale 3-8
Peony Paeonia lactiflora 3-8
Sea pink, thrift Armeria maritima 4-8
Siberian bugloss, Brunnera 3-8
perennial forget- macrophylla
me-not
Snow-in summer Cerastium 3-7
tomentosum
Spiderwort Tradescantia 4-9
andersoniana
Tree peony Paeonia 3-8
suffructicosa
Water forget-me-not Myosotis scorpiodes 3-10
Wild geranium Gernium maculatum 3-8
Yellow archangel Lamiastrum 4-9
galeobdolon
Yellow flag Iris pseudoacorus 5-9
Early Adam's needle, Yucca filamentosa 5-10
summer Spanish bayonet,
yucca
Astilbe, false Astilbe arendsii 4-9
spirea
Baby's breath Gypsophila 3-9
paniculata
Bee balm, bergamot, Monarda didyma 4-8
Oswego tea
Black-eyed Susan Rudbeckia fulgida 3-9
Blanket flower Gaillardia x 4-9
grandiflora
Blue lilyturf Liriope muscari 6-9
Carpathian Campanula carpatica 3-8
bellflower
Catmint Nepeta faasenii 3-8
Clematis Clematis hybrids 4-9
Coral bells Heuchera sanguinea 3-8
Daylily Hemerocallis spp. 3-9
Delphinium Delphinium elatum 3-7
Fernleaf yarrow Achillea filipendula 3-8
Fire pink Silene virginica 4-8
Fleabane Erigeron hybrids 3-8
Foxglove penstemon, Penstemon digitalis 4-8
beardtongue
Gas plant Dictamus albus 2-9
Goat's beard Aruncus dioicus 3-7
Jupiter's beard, Centranthus ruber 4-8
keys of heaven,
red valerian
Lance-leaved Coreopsis lanceolata 4-9
tickseed
Lupine Lupinus hybrids 4-6
Maltese cross Lychnis chalcedonica 3-9
Milfoil Achillea millefolium 3-9
Missouri primrose, Oenothera missouri- 4-8
Ozark sundrops ensis (macrocarpa)
Painter daisy, Tanacetum coccineum, 3-7
pyrethrum daisy Chrysanthemum
coccineum
Peach-leaved Campanula 3-7
bellflower persicifolia
Perennial flax Linum perenne 4-8
Pincushion flower Scabiosa caucasica 3-7
Pink coreopsis Coreopsis rosea 3-8
Salvia Salvia x sylvestris 3-8
Salvia Salvia nemorosa 3-8
Shasta daisy Leucanthemum x 5-9
superbum
Siberian iris Iris siberica 3-9
Sneezewort yarrow, Achillea ptarmica 3-9
white tansy
Soapwort Saponaria ocymoides 3-7
Spiny bear's- Acanthus spinosus 7-10
breeches
Stokes' aster Stokesia laevis 5-9
Summer forget-me- Anchusa azurea 3-8
not, Italian
bugloss
Threadleaf tickseed Coreopsis 3-8
verticillata
Tickseed, coreopsis Coreopsis 4-9
grandiflora
White gaura Gaura lindheimeri 5-9
Woolly yarrow Achillea tomentosa 3-7
Late Balloon flower Platycodon 3-9
Summer grandiflorus
Blackberry lily Belamcanda chinensis 5-10
Boltonia Boltonia asteroides 3-9
Butterfly milkweed Asclepias tuberosa 4-9
Cardinal flower Lobelia cardinalis 2-9
Creeping lily Liriope spicata 4-9
Cupid's dart Catananche caerulea 4-9
Fall anemone Anemone hybrida 4-8
False sunflower Heliopsis 3-9
helianthoides
Fascicled ironweed Vernonia fasciculata 3-8
Garden mum, hardy Dendranthema 5-9
chrysanthemum grandiflorum
Garden phlox Phlox paniculata 4-8
Globe centaurea Centaurea 3-9
macrocephala
Goldenrod Solidago cultivars 4-9
Great blue lobelia Lobelia siphilitica 4-8
Hollyhock Alcea rosea 2-8
Hosta, plantain lily Hosta species 3-8
Joe Pye weed Eupatorium maculatum 3-8
Lamb's ears Stachys byzantina 4-8
Monkshood Aconitum napellus 3-8
New England aster Aster nova-angliae 3-8
New York aster, Aster novi-belgii 3-8
Michaelmas daisy
New York ironweed Vernonia novabor- 4-9
acensis
Obedient plant, Physostegia 3-9
false dragonhead virginiana
Pearly everlasting Anaphalis 3-8
margaritacea
Plumbago, leadwort Ceratostigma 5-9
plumbaginoides
Purple coneflower Echinacea purpurea 4-8
Russian sage Perovskia atripli- 5-9
cifolia
Sea lavender Limonium latifolium 3-9
Showy sedum Sedum spectabile 3-9
Silvermound Artemesia 3-8
artemesia, schmidtiana
wormwood
Sneezeweed Helenium autumnale 3-8
Spike gayfeather, Liatris spicata 3-9
Blazingstar
Torch lily, red-hot Kniphofia hybrids 5-9
poker
Turtlehead Chelone lyonii 3-8
Veronica, spike Veronica spicata 3-9
speedwell
USDA, U.S. Department of Agriculture.
TABLE 16-4
Ornamental Grasses for Sun and Shade
COMMON SPECIES SUN OR SHADE
Blue fescue Festuca glauca Sun
Blue oat grass Helictotrichon Sun
sempervirens
Bottle-brush grass Elymus hystrix Shade
Fairy wand grass, Deschampsia Sun or shade
tufted hair grass cespitosa
Feather reed grass Calamigrostis Sun to part
acutifolia shade
Fountain grass Pennisetum Sun to part
alopecuroides shade
Golden wood millet Milium effusum Shade
'Aureum'
Hakone grass Hakonechloa macra Shade
Korean feather reed Calamagrostis Part shade or full
grass brachytricha sun if plenty
moist
Maiden grass Miscanthus Sun
sinensis
Prairie dropseed Sporobolus Sun to part
heterolepis shade
River oats Chasmanthium Shade or sun if
latifolium plenty moist
Siberian graybeard Spodiopogon Shade
sibiricus
USDA
COMMON HEIGHT ZONES
Blue fescue 1 ft. 4
Blue oat grass 2-3 ft. 4-8
Bottle-brush grass 3 ft. 4-8
Fairy wand grass, 1-2 ft. 5-9
tufted hair grass
Feather reed grass 3-6 ft. 4
Fountain grass 1-2 ft. 5
Golden wood millet 18 in. 6-9
Hakone grass 1-3 ft. 5-9
Korean feather reed 2 ft. 5-9
grass
Maiden grass 5-8 ft. 5
Prairie dropseed 15-30 in. 4
River oats 2-4 ft. 5-9
Siberian graybeard To 4 ft. 4-9
TABLE 16-5
Flowering Bulbs and Other Specialized Plant Organs for Gardens
COMMON SPECIES HEIGHT
Armenian grape Muscari 6-9 in.
hyacinth armeniacum
Crocus Crocus 4-6 in.
Daffodil Narcissus spp. 3-24 in.
(12 divisions)
Dutch hyacinth Hyacinthus 8-12 in.
orientalis
Glory-of-the- Chionodoxa 4-6 in.
snow luciliae
Grecian Anemone 3-6 in.
windflower, blanda
Greek
anemone
Lily-of-the- Convallaria 4-6 in.
valley majallis
Pasque flower Anemone 12 in.
pulsatilla
Reticulated iris Iris reticulata 4-6 in.
Siberian squill Scilla siberica 4-6 in.
Snow crocus, Crocus 4-6 in.
golden chrysanthus
crocus
Snowdrops Galanthus 4-6 in.
nivalis
Snowflake Leucojum 10-12
aestivum in.
Striped squill Puschkinia 6 in.
scilloides
Tulip (forms and Tulipa species 4-28 in.
bloom times
vary)
Winter aconite Eranthis 3-6 in.
hyemalis
Crown imperial Fritillaria
imperialis
Giant allium Allium 4-5 ft.
giganteum
Lily leek, golden Allium moly 8-12 in.
garlic
Lily, Oriental and Lilium species 2-6 ft.
Asiatic
Autumn crocus Colchicum 6-10 in.
species
Fall crocus Crocus speciosus 2-4 in.
Resurrection lily, Lycoris 15-24
magic lily, squamigera in.
surprise lily
PLANTING
COMMON DEPTH SPACING
Early Spring
Armenian grape 3 in. 3 in.
hyacinth
Crocus 2-3 in. 2-4 in.
Daffodil 6 in. (large) 3 in. 6-8 in. 3 in.
(12 divisions) (miniatures) (miniatures)
Dutch hyacinth 6 in. 6 in.
Glory-of-the- 3 in. 3 in.
snow
Grecian 3 in. 3 in.
windflower,
Greek
anemone
Lily-of-the- 3 in. 6-8 in.
valley
Pasque flower 2 in. 12 in.
Early Spring
Reticulated iris 3 in. 3 in.
Siberian squill 3 in. 3 in.
Snow crocus, 3 in. 3 in.
golden
crocus
Snowdrops 3 in. 3 in.
Snowflake 3 in. 4 in.
Striped squill 3 in. 3 in.
Tulip (forms and 4-6 in. 4-6 in.
bloom times
vary)
Winter aconite 2-3 in. 3 in.
Crown imperial
Giant allium 6 in. 12 in.
Lily leek, golden 4 in. 4-6 in.
garlic
Lily, Oriental and 6 in. 6 in.
Asiatic
Late Summer
Autumn crocus 5 in. 4-6 in.
Fall crocus 3-5 in. 3-9 in.
Resurrection lily, 6 in. 6 in.
magic lily,
surprise lily
USDA
COMMON ZONES OTHER
Armenian grape 3-8 Blue-violet
hyacinth
Crocus 3-8 Yellow,
purple,
white
Daffodil 4-8 White,
(12 divisions) yellow,
orange,
bicolors
Dutch hyacinth 4-8 White, blue,
purple,
pink,
salmon,
yellow
Glory-of-the- 3-9 Violet to
snow blue,
white,
pink
Grecian 5-9 Blue, white,
windflower, pink
Greek
anemone
Lily-of-the- 3-8 White, pink
valley
Pasque flower 5-8 Purple, red,
creamy
white
Reticulated iris 4-8 Blue to
violet
with
yellow
coloring
on each
falls
Siberian squill 3-9 Blue, with
dark
blue
stripe
outside
petals
Snow crocus, 3-8 Yellow,
golden white,
crocus lavender,
bicolors
Snowdrops 3-9 White
Snowflake 4-9 White
Striped squill 3-10 Whitish blue
with
blue
stripe
Tulip (forms and 5-8 All except
bloom times true blue
vary)
Winter aconite 3-7 Yellow
Crown imperial Red-orange,
orange,
yellow
Giant allium 5-8 Lavender
Lily leek, golden 4-8 Yellow
garlic
Lily, Oriental and 4-8 Cream,
Asiatic white,
yellow,
orange,
pink,
red,
lavender
Autumn crocus 5-9 Pink, lilac,
white
Fall crocus 4-8 White,
lavender,
violet
Resurrection lily, 5-9 Pink
magic lily,
surprise lily
TABLE 16-6
Select Ferns and Their Hardiness
HARDINESS
COMMON NAME SPECIES ZONE
Autumn fern Dryopteris erythrosora 5-9
Christmas fern Polystichum 3-9
acrostichoides
Cinnamon fern Osmunda cinnamomea 3-10
Clayton's fern Osmunda claytoniana 3-8
Five-finger Adiantum aleuticum 4-9
maidenhair
Fortune's holly Cyrtomium fortunei 6-11
fern
Golden-scaled Dryopteris affinis 4-8
male fern
Hart's tongue Asplenium 6-8
fern scolopendrium
Himalayan Adiantum venustum 4-8
maidenhair
Holly fern Cyrtomium falcatum 7-11
Japanese painted Athyrium niponicum 3-8
fern
Lady fern Athyrium filix-femina 3-8
Leather wood Dryopteris marginalis 4-8
fern
Makino's holly Polystichum makinoi 5-8
fern
Ostrich fern Matteuccia struthiopteris 2-8
Royal fern Osmunda regalis 3-10
Soft shield fern Polystichum setiferum 4-9
Southern Adiantum capillus- 6-9
maidenhair veneris
Western sword Polystichum munitum 5-9
fern
TABLE 16-7
Vines and Their Growth Habit and Hardiness Zone
COMMON BOTANICAL
NAME NAME HABIT
Bittersweet Celastrus scandens Woody vine with
small, decorative
orange fruits
Black-eyed Thunbergia alata Vining 6-10 ft.
Susan vine plant with orange
-yellow flowers
Boston ivy Parthenocissus Primarily sun-loving,
tricuspidata three-lobed leaves
with grasping
tendrils.
Clematis Clematis spp. Vine with early or
late summer
flowers
Climbing Hydrangea Flat-topped clusters
hydrangea anomala var. of white flowers
petiolaris in spring; climbs
walls; exfoliating
bark, large,
heart-shaped
leaves
Honeysuckle, Lonicera x Bright, fragrant,
goldflame heckrottii orange-red tubular
flowers
Morning glory Ipomoea tricolor Summer bloomer
with white, pink
or blue flowers
Scarlet clematis Clematis texensis Bright crimson,
um-shaped flowers
on spreading
shrubby groundcover
Trumpet vine, Campsis Woody, deciduous
trumpet grandiflora, vine; vigorous
creeper Campsos grower that
radicans may become
invasive
Virginia Parthenocissus Vigorous shade- and
creeper quinquefolia sun-tolerant vine;
grasping tendrils
that attach to
solid surfaces;
palmate compound
leaves
Wintercreeper Euonymus fortunei Creeping groundcover
or bushy plant
with slender stems
that require
support to climb;
leaf variegations
numerous
Wisteria Wisteria spp. Showy vine for arbors,
pergolas; purple
or white flower
clusters in late
spring
COMMON HARDINESS
NAME ZONE
Bittersweet 3-8
Black-eyed Annual
Susan vine
Boston ivy 4-8
Clematis 4-8
Climbing 5-7
hydrangea
Honeysuckle, 5-9
goldflame
Morning glory Annual
Scarlet clematis 4-8
Trumpet vine, 4-10
trumpet
creeper
Virginia 4-9
creeper
Wintercreeper 5-8
Wisteria 5-9
TABLE 16-8
Colors and Cultivars
ANNUAL
COLOR COMMON NAME SPECIES (A) OR
PEREN-
NIAL (P)
Red Geranium Pelargonium x A
hortorum
New Guinea impatiens Impatiens x hawkeri A
Petunia Petunia x hybrida A
Canna lily Canna indica A
Salvia Salvia splendens A
Crocosmia Crocosmia A
Blanket flower Gaillardia x A
grandiflora
Lobelia Lobelia cardinalis A
Beebalm Monarda didyma P
White Flowering tobacco Nicotiana spp. A
Shasta daisy Leucanthemum x P
superbum
Chrysanthemum, mums Dendranthema x P, A
grandiflorum
Lily-of-the-valley Convallaria majalis P
White gaura Gaura lindheimeri P
Garden geranium Pelargonium x A
hortorum
Hardy geranium Geranium spp. P
Oriental and Asiatic Lilium spp. P
Lily
Penstemon, Penstemon digitalis P
beardtongue
Phlox Phlox spp. P
Salvia Salvia spp. P, A
Foam flowers Tiarella spp. P
Verbena Verbena spp. A
Flowering chives Allium tuberosum P
Pearly everlasting Anaphalis P
margaritacea
Blue Sky blue aster Aster azureus P
Forget-me-not Myosotis sylvatica A
Perennial forget Myosotis scorpiodes P
-me-not
Siberian bugloss Brunnera macrophyla P
Summer forget-me-not Anchusa azurea A
Iris Iris spp. P
Blue salvia Salvia spp. P
Flax Linum spp. P
Delphinium Delphinium elatum P
Lobelia Lobelia erinus P
Yellow Marigold Tagetes spp. A
Daylily Hemerocallis spp. P
Iris Iris pseudacorus P
Sunflower Helianthus annuus A
Zinnia Zinnia angustifolia A
Yarrow Achillea spp. P
Basket-of-gold Aurinia saxatilis P
Chrysanthemum Dendranthema x P
grandiflorum
Coreopsis Coreopsis spp. P
Leopard's bane Doronicum orientale P
Foxtail lily Eremurus stenophyllus P
Evening primroses Oenothera spp. P
Black-eyed Susan Rudbeckia fulgida P
Goldenrod Solidago spp. P
Golden marguerite Anthemis tinctoria P
Orange Mexican sunflower Tithonia rotundifolia A
Chilean avens Geum chiloense P
'Tango' New Guinea Impatiens wallerana A
impatiens
Butterfly milkweed Asclepias tuberosa P
Zinnia Zinnia angustifolia A
Poppy Papaver spp. P
Daylily Hemerocallis spp. P
Purple Butterfly bush Buddleia davidii P
Geranium Geranium maculatum P
Spipke gayfeather Liatris spicata P
Petunia Petunia x hybrida A
Heliotrope Heliotrope arborescens A
Stoke's aster Stokesia laevis P
Bellflower species Campanula spp. P
Pink Impatiens Impatiens wallerana A
Astilbe Astilbe x arendsii P
Hollyhock Alcea rosea P
Dianthus, pinks Dianthus spp. P
Bleeding heart Dicentra spectabilis P
Green- Lamb's ears Stachys byzantina P
gray
foliage
Dusty Miller Senecio cineraria A
Artemesia, wormwood Artemesia schmidtiana P
TABLE 16-9
Flower Heights of Selected Annuals
HEIGHT COMMON NAME SPECIES
Short ([greater Ageratum Ageratum
than or equal
to] 6 in.) Alyssum Alyssum
Portulaca Portulaca
Viola Viola
Medium-short Cabbage/kale (ornamental) Brassica
(6-12 in.)
Calendula, pot marigold Calendula
Calibrachoa Calibrochoa
Celosia Celosia
Impatiens Impatiens wallerana
Lobelia Lobelia
Marigold, French Tagetes
Nasturtium Nasturtium
Pansy Viola
Periwinkle Catharanthus
Petunia Petunia x hybrida
Primrose Primula
Verbena Verbena
Viola Viola Xwittrockiana
Medium Argyranthemum Argyranthemum
(12-18 in.)
Cuphea Cuphea
Gazania Gazania
Geranium Pelargonium
Gomphrena, globe amaranth Gomphrena
Gypsophila Gypsophila
Impatiens, New Guinea Impatiens x hawkeri
Pentas Pentas lanceolata
Salvia, mealy-cup Salvia
Snapdragons Antirrhinum
Stock Matthiola incana
Medium tall Carnation Dianthus
(18-24 in.)
Celosia Celosia
Dusty Miller Senecio cineraria
Gaillardia Gaillardia
Heliotrope Heliotropium
arborescens
Marigold, African Tagetes erecta
Nemesia Nemesia
Pentas Pentas lanceolata
Black-eyed Susan Rudbeckia
Sage, scarlet Salvia coccinea
Zinnia Zinnia elegans
Tall (>24 in.) Amaranth Amaranthus
Cleome, spider flower Cleome hasslerana
Hollyhock Alcea rosea
Morning glory (vine) Ipomoea
Nicotiana Nicotiana
Sunflower Helianthus
Sweet pea (vine) Lathyrus latifolius
TABLE 16-10
Heights of Selected Perennials
USDA
HARDINESS
HEIGHT COMMON NAME SPECIES ZONE
Low-growing: Basket-of-gold Aurinia saxatilis 3-7
12 in. and
under Bishop's weed Aegopodium podagaria 4-8
Bugleweed Ajuga reptans 4-9
Carpathian Campanula carpatica 3-8
bellflower
False rockcress Aubrieta deltoidea 4-8
Maiden pink Dianthus deltoides 4-9
Red barrenwort Epimedium rubrum 4-8
Rockcress Arabis caucasica 4-7
Snow-in-summer Cerastium tomentosum 3-7
Medium: Bleeding heart Dicentra spectabilis 4-9
12-24 in.
Columbine Aquilegia hybrids 3-9
Everlasting Anaphalis 3-8
triplinervis
Heartleaf Bergenia cordifolius 3-8
bergenia
Lady's mantle Alchemilla mollis 4-7
Lilyleaf Adenophorum 4-8
ladybell liliifolia
Mountain bluet Centaurea montana 3-8
Needle-leaf Coreopsis 3-9
tickseed, verticillata
Threadleaf
coreopsis
Pink coreopsis, Coreopsis rosea 3-9
pink tickseed
Siberian bugloss Brunnera macrophylla 3-8
Silvermound Artemisia schmidtiana 3-7
artemesia 'Nana'
Sweet William Dianthus barbatus 3-9
Medium tall: Anemone Anemone x hybrida 4-8
24-48 in.
Astilbe Astilbe x arendsii 3-8
Blackberry lily Belamcanda chinensis 5-10
Blanket flower Gaillardia x 3-10
grandiflora
Blue wild indigo Baptisia australis 3-9
Butterflyweed Asclepias tuberosa 3-9
Chrysanthemum, Dendranthema x 5-9
Mum morifolium
Golden Marguerite Anthemis tinctoria 3-7
Hardy begonia Begonia grandis 6-9
Jupiter's beard Centranthus ruber 5-8
Michaelmas daisy, Aster nova-belgii 4-8
New York aster
New England aster Aster nova-angliae 4-8
Peach-leaved Campanula 3-7
bellflower persicifolia
Pink turtlehead Chelone lyonii 3-8
Purple coneflower Echinacea purpurea 3-8
Spiny bear's Acanthus spinosus 5-10
breeches
Ticksseed Coreopsis grandiflora 4-9
White gaura Gaura lindheimeri 5-9
Willow amsonia Amsonia 3-9
tabernaemontana
Yarrow, achillea Achillea spp. 4-8
Tall: >48 in. Boltonia Boltonia asteroides 4-9
Delphinium Delphinium elatum 3-7
Goat's beard Aruncus dioicus 3-7
Hollyhock Alcea rosea 3-8
Italian bugloss Anchusa azurea 3-8
Monkshood Aconitum napellus 4-8
TABLE 16-11
Plants Deer Prefer Not to Eat
COMMON NAME SPECIES NAME
Yarrow Achillea millefolium
Ageratum Ageratum houstonianum
Ornamental onion Allium spp.
Snapdragon Antirrhinum majus
Columbine Aquilegia hybrids
Astilbe, false spirea Astilbe x arendsii
Larkspur Consolida ambigua
Bleeding heart Dicentra spectabilis
Purple coneflower Echinacea purpurea
Sunflower Helianthus annuus
Heliotrope Heliotropus arborescens
Hellebore, Lenten rose Helleborus orientalis
Candytuft Iberis sempervirens
Iris Iris spp.
Lavender Lavandula spp.
Flax Linum perenne
Lobelia Lobelia erinus
Sweet alyssum Lobularia maritima
Stock Matthiola incana
Four-o'clock Mirabilis jalapa
Daffodils Narcissus spp.
Russian sage Perovskia atriplicifolia
Petunia Petunia x hybrida
Lungwort Pulmonaria saccharata
Salvia Salvia spp.
Marigold Tagetes spp.
Nasturtium Tropaeolum majus
Periwinkle Vinca major
Yucca Yucca spp.
TABLE 16-12
Perennials That Respond Well to Pruning
USDA
HARDINESS
COMMON NAME SPECIES ZONE
Autumn Joy sedum Sedum 'Autumn Joy' 3-9
Beebalm Monarda didyma 4-9
Black-eyed Susan Rudbeckia fulgida 2-10
Boltonia, false chamomile Boltonia asteroides 3-8
Campion, catchfly Lychnis coronaria 2-10
Chrysanthemum, mum Dendranthema x morifolium
Culver's root Veronicastrum virginicum 3-8
False sunflower, ox-eye Heliopsis helianthoides 4-9
Feverfew, tansy Tanacetum parthenium 3-10
Flax Linum perenne 2-10
Garden phlox Phlox paniculata 3-9
Gaura Gaura linheimeri 3-10
Goldenrod Solidago spp. 3-9
Helenium, sneezeweed Helenium autumnale 3-9
Hibiscus, mallow, rose mallow Hibiscus moscheutos 3-10
Hollyhock Alcea rosea 2-9
Joe-pye weed Eupatorium maculatum 3-10
Ladybells, gland bellflower Adenophorum liliifolia 3-9
Lavender Lavandula spp. 5-9
Lobelia Lobelia cardinalis 1-10
Mallow, musk mallow Malva alcea 3-10
Marguerite daisy Anthemis tinctoria 4-9
Meadow phlox Phlox maculata 3-8
Michaelmas daisy Aster nova-belgii 2-9
Monkshood Aconitum napellus 3-8
New England aster Aster nova-angliae 2-9
New York ironweed Vernonia novaboracensis 5-9
Obedient plant Physostegia virginiana 3-9
Purple coneflower Echinacea purpurea 3-9
Rock rose, sun rose Helianthemum nummularium 6-9
Russian sage Perovskia atriplicifolia 5-9
St. John's wort Hypericum calycinum 5-9
Sunflower Helianthus salicifolius 1-10
Wormwood Artimisia schmidtiana 2-10
Yarrow, achillea, milfoil Achillea millefolium 3-10
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| |
| Author: | Loehrlein, Marietta M. |
|---|---|
| Publication: | Home Horticulture: Principles and Practices |
| Date: | Jan 1, 2008 |
| Words: | 11072 |
| Previous Article: | Chapter 15: turfgrass. |
| Next Article: | Chapter 17: ornamental trees, shrubs, and groundcovers. |
| Topics: | |