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Chapter 19: Flowers and foliage.

People grow a variety of flowers and foliage as a business to sell to other people for various occasions and to decorate their surroundings. To commercially produce flowers and foliage requires knowledge of the specific cultural practices for each type of plant whether it is grown outdoors or in a greenhouse. These plants can be perennials, biennials, or annuals.


After completing this chapter, you should be able to:

* Name four types of flowers or foliage plants that people purchase at different times of the year

* Describe the time range from planting flowers until the flowers produce income

* Identify the pH range for perennial plants

* Describe watering precautions for some flowers and foliage

* Discuss planting of perennials and annuals

* Explain the winter care of perennials

* Name two methods of asexually propagating perennials

* Discuss considerations when selecting seed

* Describe an indoor starting media

* Explain how to transplant flowers or foliage outdoors

* IIdentify four types of bulb

* Discuss how bulbs can be forced

* Identify the light requirements of flowering houseplants

* Name four common indoor flowering plants

* Describe the greenhouse environment

* List five pests of bulbs

Key Terms



bare root







cold frames

Flower Business

People buy flowers and foliage for various reasons and at different times of the year as Table 19-1 shows. Successful growers recognize the specific times certain flowers and foliage are purchased and how long these take to produce so they can have product ready when the customer is ready to buy. Table 19-2 shows the average time from plant to sales for different flower and foliage crops.

Flowers and foliage are adapted to a variety of growing conditions and climates as Table 19-3 shows. These conditions need to be considered unless a greenhouse is used.

Value of Floriculture

Not counting the value of personal flower gardens, floriculture in the United States has a total value of about $3 billion annually. Bedding plants, pulled flowers, foliage, cut flowers, and cut greens all contribute to the value of floriculture. And as Table 19-4 shows, some states lead in floriculture. Figure 19-1 illustrates the trends in floriculture production over several years.

Flowering Herbaceous Perennials

Perennial plants live for many years after reaching maturity, producing flowers and seeds each year. Perennials are classified as herbaceous if the top dies back to the ground each winter and new stems grow from the roots each spring. They are classified as woody if the top persists, as in shrubs or trees. Most garden flowers are herbaceous perennials meaning the tops of the plants, the leaves, stems, and flowers die back to the ground each fall with the first frost or freeze (see Table 19-5). Every spring, new plant tops arise from the roots, which persist through the winter. Any plant that lives through the winter is said to be hardy.


There are advantages to perennials, the most obvious being that they do not have to be set out, like annuals every year. Some perennials, such as delphiniums, have to be replaced every few years. Another advantage is that with careful planning a perennial flower bed will change colors, as one type of plant finishes and another variety begins to bloom. Also, since perennials have a limited blooming period of about two to three weeks, deadheading, or removal of old blooms, is not as frequently necessary to keep them blooming. However they do require pruning and maintenance to keep them attractive, as the rose in Figure 19-2. Their relatively short bloom period is a disadvantage, but by combining them with annuals, a continuous colorful show can be provided. Most require transplanting every three years.

Growing Perennials

While perennials do not require replanting each year, as do annuals, they still require care. For best results, initial planning, proper soil preparation, and occasional maintenance are necessary. With proper attention to these details, a perennial garden can provide color and interest in the landscape throughout the growing season.


The site will influence what species of perennials can be grown. Most flowering perennials prefer six to eight hours of sun per day, making a southeast exposure ideal. Areas of shade will reduce the numbers of species that can be grown. Exposure to wind will vary depending on the site, and thought should be given to wind protection, particularly if growing taller perennials such as delphinium or lilies.



The perennial garden is important to insure continued bloom and desired combinations of color, texture, and height. Growers should draw a plan of the garden to scale using graph paper. Most perennials have a limited period of bloom, and growers choose plants to give a succession of flowering. This requires selecting a range of perennials, which have flowering periods that collectively cover the whole growing season. The blooming period of a particular species can usually be classified as spring, early summer, midsummer, or late summer/ fall. A properly planned perennial garden will include plants from each of these flowering groups to create a season-long succession of bloom throughout the garden.

Perennials look best when planted in drifts of several plants, rather than as single plants or in rows. A rough guide for spacing would be 6 to 12 inches between dwarf plants, 12 to 18 inches between medium-sized plants, and 18 to 36 inches between tall perennials. Plant taller species toward the back of a flower border.

Soil Preparation

This is probably the most important factor in determining the success of a perennial planting. Soil with good water drainage is necessary. It is particularly important that the soil not stay excessively moist during the winter dormant period. Incorporating organic matter such as compost or peat moss helps improve soil drainage. Spading or rototilling the soil to a minimum depth of 8 to 10 inches is also important. Soil preparations should be done in the fall or even one year ahead to remove all weeds that may germinate. With poor soil conditions, raised beds containing improved soil are better. Most perennials grow best in soil with a pH range of 6.5 to 7.0. A soil test can be made to determine the soil pH. Make any needed adjustments before planting.

Application of total vegetation killers can be added to beds before planting also. These chemicals control quack grass, thistle, and other perennial grasses and broadleaf weeds well. Read and follow all label directions.


Perennials are generally planted in the spring (April to May). Plants bought from mail-order nurseries are often shipped bare root, not potted. Growers should plant these as soon as possible after receiving. Container-grown (potted) perennials can be planted throughout the growing season, but spring is generally preferred. The proper time to plant will depend on how these perennials were produced by the grower.

Container-grown plants that have been exposed to outside temperatures throughout the winter can be planted as soon as the soil can be worked, about the same time as trees and shrubs. Perennials produced in a greenhouse during winter should not be planted until after danger of frost (below 32[degrees]F) is past, much like annual bedding plants and vegetable transplants.

If planting in loose soil, plant crowns may end up higher than planned. If soil does settle after planting, add mulch or additional soil to cover exposed crowns. Growers need to get rid of weeds before planting. Once the plants are in, the weeds are harder to remove.

Perennials can be planted in spring or fall, anytime the soil is workable and plants are available. Dormant plants are set out in early spring, four to six weeks before the last frost. Actively growing plants can be planted spring through fall. Perennials do best if planted before October 1 because roots can establish themselves before the ground freezes. Use stakes to mark where the plants will be set. A hole should be dug large enough to provide space for the roots. If the weather does not allow for immediate planting, growers need to keep plants in a cool, dark spot and make sure the peat moss around the roots does not dry out.


Although water requirements of perennials can vary greatly from species to species, most require supplemental watering until well established. One inch of water per week is a general rule. Once established, many species require watering only during prolonged dry periods. Selection of species adapted to drier climates will help reduce the need for supplemental watering.

Occasional overhead watering can harm perennials by causing disease and resulting in a shallow root system less able to withstand periodic dryness. Less frequent, more thorough watering applied directly to the soil is better.


Fertility of the soil can be improved before planting with the incorporation of a complete fertilizer, such as 4-12-4 or 5-10-5 at a rate of 2 to 3 pounds/100 square feet. Avoid turf fertilizers high in nitrogen as these may promote excessive foliage production at the expense of a strong root system and good flower production. With proper soil preparation and improvement of soil fertility before planting, most perennials require little additional fertilization. Application of a "starter" fertilizer when perennials are first planted may aid in more rapid establishment of a good root system. For established plants, a little bone meal or super phosphate (0-19-0) worked into the soil around the plant in the spring can be beneficial.


Once established, most perennials require only routine maintenance. Taller species may require staking, particularly in windy areas. Staking is best done when plants are first sending up new growth, before they have become top heavy. Pinching back new growth may produce bushier plants that are less likely to require staking.

A mulch applied to the soil will help suppress weeds while conserving moisture. Do not place a mulch too close to the crown as this may hold excess moisture and result in disease problems.

Insects and diseases are generally not severe threats to most perennials, particularly if locally adapted species are selected and proper care is given to the plants.

Winter Protection

Perennials damaged or killed during the winter are not usually injured directly by cold temperatures, but indirectly by frost heaving. Frost heaving occurs when the soil alternately freezes and thaws, resulting in damage to the dormant crown and root system. This action can be reduced by a winter mulch, which helps prevent rapidly fluctuating soil temperatures. A mulch about 3 inches thick is best. Evergreen boughs, clean straw, or other loose, coarse materials are good mulches. Materials such as tree leaves or grass clippings may compact too much around the plant, inhibiting water drainage and promoting disease development. Apply winter mulches after the ground freezes, usually in late November. Unless the perennials are evergreen, cut back the dead foliage to about six inches before applying the mulch, and discard the dead foliage and other debris. In the spring, mulch is gradually removed as new growth develops.

Dividing and Transplanting

Most perennials can be divided. Periodic division is needed to maintain vigor and maximum flower production. It is usually done every three to four years. Some perennials should never be divided.

The time of year when perennials are divided is a major factor in determining the success of this procedure. Species that bloom from midsummer to the fall are best divided in the early spring, before much new growth has begun. Perennials that bloom in the spring or early summer should be divided in the fall, or after the foliage dies. Exceptions are iris and daylilies, which are divided immediately after flowering.

To divide a perennial, the plant is removed from the soil by digging around and under the entire plant and lifting it carefully from the soil to avoid as much root damage as possible. All adhering soil is dislodged by hand or with a gentle stream of water from a hose. Growers should remove and discard diseased parts and cut back the top of the plant (stems, shoots, leaves) to about 6 inches. Divisions are usually taken from the outer perimeter of the plant, as this younger area tends to produce more vigorous growth. The plant can be divided by carefully breaking it apart by hand or by cutting with a heavy, sharp knife. Divide the plant in such a way that each new division has three to five "eyes"--buds that will produce new shoots.

Growers should replant the new divisions as soon as possible. They also should rework the soil if necessary to improve drainage and structure. A winter mulch is needed for divisions that are replanted in late summer or fall to help prevent frost heaving.

Ethylene ([C.sub.2][H.sub.4) is considered to be a plant hormone, a
growth regulator, and a potentially harmful pollutant of ornamental
crops. It has sometimes been called the death hormone, because it
promotes the aging and ripening of many fruits and flowers. It is a
simple organic substance that is active at very low concentrations.
Ethylene and related substances are produced when almost any
material is incompletely burned. It also evolves naturally from
plant materials that are aging, ripening, or rotting. Many ripening
fruits and vegetables generate ethylene as do certain

Ethylene toxicity and damage is of particular importance in the
shipping and handling of floral produces. Ethylene gas is often
added to banana ripening rooms at food wholesalers. This can cause
problems for floral products if they are handled and distributed
from the same building.

Symptoms of excess ethylene include malformed leaves and flowers;
thickened stems and leaves; abortion of leaves and flowers;
abscission of leaves and flowers; excessive branching and shortened
stems. Hastened senescence (aging) of cut flowers occurs when they
are exposed to ethylene. Flower corms or bulbs should never be
stored with apples, because serious injury occurs. Fusarium spp.
disease organisms give off ethylene and can cause flower abortion
of tulips and delayed bud activity in roses. Many flowers such as
carnations will begin to age in a matter of hours, and snapdragon
and geranium florets will prematurely shatter after exposure to
only twenty parts per billion (ppb). Some plants are far more
sensitive to ethylene than others. Orchids, carnations, gypsophila,
delphinium, and antirrhinums are extremely sensitive, whereas roses
and chrysanthemums appear to be more tolerant.

Fumes from welding, auto exhaust, and local trash burning can cause
extensive damage to greenhouse crops. Natural and propane gases are
normally free of impurities and burn very cleanly. However, near
perfect or complete combustion must occur when gas burners are used
in or near greenhouses. Burners must have proper exhaust venting
with no leaks, and they must have adequate air (oxygen) intake for
proper combustion.

Not all harmful forms of ethylene are from external sources. At
certain times, endogenous ethylene products, that is, ethylene
produced within the plants themselves, can contribute to premature
senescence of flowers. This can happen whenever plants or cut
flowers are mishandled or stored improperly.

Finally, ethylene is not all bad for floriculture. It is used to
induce flowering in bromeliads, and has been used successfully as a
growth regulator and a chemical pinching agent in some floriculture

Diseases and Insects

Perennials in general are healthy plants. Producers should select resistant varieties. They plant perennials in conditions of light, wind, spacing, and soil textures that are suited to them. After planting, the spent flowers, dead leaves, and other plant litter should be removed as these serve as a source of reinfestation. Growers need to know the major insect and disease pests (if any) of each specific plant type grown so that problems can be correctly diagnosed and treated as they arise.


Plants can be propagated from tip or root cuttings.

Flowering Annuals

Annual flowers live only one growing season during which time they grow, flower, and produce seed, thereby completing their life cycle. Annuals must be set out or seeded every year since they do not persist. Some varieties will self-sow or naturally reseed themselves. This may be undesirable in most flowers because the parents of this seed are unknown and hybrid characteristics will be lost. Plants will scatter everywhere instead of their designated place. Examples are alyssum, petunia, and impatiens. Some perennials, plants that live from year to year, are classed with annuals because they are not winter hardy and must be set out every year, such as begonias and snapdragons. Annuals have many positive features. They are versatile, sturdy, and relatively cheap. Plant breeders have produced many new and improved varieties. Annuals are easy to grow, produce instant color, and most important, they bloom for most of the growing season.

There are a few disadvantages to annuals. They must be set out as plants or sowed from seed every year, which involves some effort and expense. Old flower heads should be removed on a weekly basis to insure continuous bloom. If they are not removed, the plants will produce seed, complete their life cycle, and die. Many annuals begin to look worn out by late summer and need to be cut back for regrowth or replaced.

Annuals offer the gardener a chance to experiment with color (as in the petunias in Figure 19-3), height, texture, and form. If a mistake is made, it is only for one growing season.

Annuals are useful for the following:

* Filling in spaces until permanent plants are installed

* Extending perennial beds

* Filling in holes where an earlier perennial is gone or the next one has yet to bloom

* Covering areas where spring bulbs have bloomed and died back

* Filling planters, window boxes, and hanging baskets

* Planting along fences or walks

* Creating seasonal color


Site Selection and Preparation

Different annuals perform well in full sun, light shade, or heavy shade. Light, soil characteristics, and topography should be considered. The slope of the site will affect temperature and drainage. Also, the texture, fertility, and pH of the soil will influence the plant's performance.

Preparing the soil in the fall is the best time. Proper preparation of soil will increase success in growing annuals. Growers first have the soil tested and adjust the pH if needed. Check and adjust drainage. If drainage is poor, growers may plan to plant in raised beds. The next step is to dig the bed. Often growers will add 4 to 6 inches of organic matter to heavy clay to improve soil texture. They dig to a depth of 12 or 18 inches and leave until fall or early spring. In spring, fertilizer is added, the area is spaded again, and the surface is raked smooth.

Seed Selection

To get a good start toward raising vigorous plants, growers always buy good viable seed packaged for the current year. Seed saved from previous years usually loses its vigor. It tends to germinate slowly and erratically and produces poor seedlings. Seed needs to be kept dry and cool until planted. If seed must be stored, it should be placed in an airtight container, refrigerated, and stored with a material that will absorb excess moisture. Growers should buy hybrid varieties. Plants from hybrid seed are more uniform in size and more vigorous than plants of open pollinated varieties. They usually produce more flowers with better substance.

Starting Plants Indoors

The best media for starting seeds is loose, well drained, fine textured, low in nutrients, and free of disease causing fungi, bacteria, and unwanted seeds. Many commercial products meet these requirements.

Clean containers are filled about two-thirds full with potting medium. The medium is leveled and moistened evenly throughout. It should be damp but not soggy. A furrow is made 1/4 inch deep. Large seeds are sown directly into the bottom of the furrow. Before sowing small seed, growers fill the furrow with vermiculite, and then sow small seed on the surface of the vermiculite. Seed may be sown in flats following seed package directions or directly in individual peat pots or pellets, two seeds to the pot.

After seed is sown, all furrows are covered with a thin layer of vermiculite, then watered with a fine mist. A sheet of plastic may be placed over seeded containers and then they are set in an area away from sunlight where the temperature is between 60[degrees] and 75[degrees]F. Bottom heat is helpful.

As soon as seeds have germinated, the plastic sheeting is removed and seedlings are placed in the light. If natural light is poor, fluorescent tubes can be used. Seedlings should be placed close to the tubes. After plastic is removed from the container, the new plants need watering and fertilizing, since most planting material contains little or no plant food. Growers use a mild fertilizer solution after plants have been watered.

When seedlings develop two true leaves, plants are thinned in individual pots to one seedling per pot. Those in flats, such as the seedlings in Figure 19-4, are transplanted to other flats, and spaced 1 1/2 inches apart, or to individual pots.


Planting Times

As a general rule, growers delay sowing seeds of warm weather annuals outdoors or setting out started plants until after the last frost date. Seeds of warm weather annuals will not germinate well in soils below 60[degrees]F. If soil is too cold when seed is sown, seeds will remain dormant until soil warms and may rot instead of germinating. Some cold-loving annuals should be sown in late fall or very early spring.

Sowing Seed Outdoors

To seed annuals successfully, growers sow seed in vermiculite filled furrows. Annuals seeded in the garden frequently fail to germinate properly because the soil hardens on the surface keeping the water out. The furrows in soil are about 1/2 inch deep. If soil is dry, producers water the furrow, and then fill it with fine vermiculite and sprinkle with water. Make another shallow furrow in the vermiculite and sow the seed in this furrow. Seed should be sown at the rate recommended on the package. Mulch can be used until the plants are receiving enough sunlight.

Setting Out Transplants

By setting out started plants in the garden, producers can have a display of flowers several weeks earlier than if sown by seeds of the plants. This is especially useful for annuals that germinate slowly or need several months to bloom. Started plants can be purchased or produced. Buy only healthy plants free of pests and diseases.

Before setting out transplants, growers harden them off by setting the plants outside during the day. After the last frost date, annual plants may be set out. A hole is dug for each plant large enough for the root system to fit comfortably. Plants are lifted out from the flat with a block of soil surrounding their roots.

Setting Plants

If plants are in fiber pots, growers remove the paper from the outside of the root mass and set the plant in a prepared planting hole. When setting out plants in peat pots, growers set the entire pot in the hole but remove the upper edges of the pot so that all of the peat pot is covered when soil is firmed around the transplant. If a lip of the peat pot is exposed above the soil level, it may produce a wick effect, pulling water away from the plant and into the air. After setting the plants, growers water them and provide protection against excessive sun, wind, or cold if needed while the plants are getting settled in their new locations. Inverted pots, newspaper tunnels, or cloaks can be used.


When most outdoor-grown annuals develop the first pair of true leaves, they should be thinned to the recommended spacing. This spacing allows plants enough light, water, nutrients, and space for them to develop fully above and below the ground. If they have been seeded in vermiculite filled furrows, excess seedlings can be transplanted to another spot without injury. Zinnias are an exception to this rule of thinning. In many varieties of zinnias, flowers will appear with a large nearly naked corolla and few colorful petals. This phenomenon is sometimes referred to as Mexican hats. To avoid such plants, growers sow two or three seeds at each planned location. Then they wait until the plants bloom for the first time, and remove the plants with this undesirable characteristic. Next, the remaining plants are thinned to the recommended 8- to 12-inch spacing.


Growers do not rely on summer rainfall to keep flower beds watered. They plan to irrigate them from the beginning. The entire bed needs to be moistened thoroughly, but not watered so heavily that the soil becomes soggy. After watering, soil is allowed to dry moderately before watering again. Drip systems are good for watering.

Sprinklers are not as effective as soaker hoses. Water from sprinklers wets the flowers and foliage making them susceptible to diseases. Structure of the soil may be destroyed by impact of water drops falling on its surface. The soil may puddle or crust, preventing free entry of water and air.


Mulches help keep the soil surface from crusting and aid in preventing growth of weeds. Organic mulches can add humus to the soil. Grass clippings make a good mulch for annuals, if they do not mat. Sheet plastics also may be spread over the soil surface to retard evaporation of water and to prevent growth of weeds.


After plants are set out or thinned, cultivate only to break the crusts on the surface of the soil. When the plants begin to grow, stop cultivating and pull weeds by hand. As annual plants grow, feeder roots spread between the plants. Cultivation may injure these roots. In addition, cultivation stirs the soil and uncovers weed seeds that germinate.

Deadheading (Removing Old Flowers)

To maintain vigorous growth of plants, and assure neatness, growers remove spent flowers and seed pods. This step is particularly desirable if growing ageratum, calendula, cosmos, marigold, pansy, scabiosa, or zinnia.


Tall growing annuals like larkspur or tall varieties of marigold or cosmos need support to protect them from bad weather. Tall plants are supported by stakes of wood, bamboo, or reed large enough to hold the plants upright but not large enough to show. Stakes should be about 6 inches shorter than the mature plant so the blossom can be seen. Staking begins when plants are about one-third their mature size. Stakes are placed close to the plant but not so close as to damage the root system. The stems of the plants are secured to stakes in several places with paper-covered wire or other materials that will not cut into the stem. Plants with delicate stems can be supported by a framework of stakes and strings in crisscrossing patterns.


When preparing beds for annuals, fertilizer should be added according to recommendations given by soil sample analysis, or by seeing plants that have grown on the site. Lime may also be needed if the soil test results indicate. Dolomitic limestone should be used rather than hydrated lime. Ideally, lime should be added in the fall so it will have time to change the pH. Fertilizer should be added in the spring so it will not leach out before plants can benefit from it.

Additional fertilizers may be needed after annuals have germinated and started to grow. This is especially true if organic mulches are added because microorganisms decomposing the mulch take up available nitrogen. A fertilizer high in nitrogen should be used in these situations. Work the fertilizer in the soil around the plants being careful not to touch the stems. Fertilizers should be applied to damp soil.


People use the term bulbs to refer to corms, tubers, and rhizomes. While all these structures contain an embryonic plant and stored plant food, they are all different in appearance and their method of propagation. Bulbs are also used in wooded areas with evergreen ground covers, in rock gardens, with evergreen shrubs to add color, and as cut flowers.

Site Selection and Soil

Bulbs grow well in well-drained loam. To improve soil texture, organic matter can be added to the soil in the form of compost, bark, and manure. Neutral soil (pH 7) is best for bulbs. Limestone can be added if the pH is below 6.

Planting Bulbs

Growers plant bulbs with a bulb planter, nursery spade, or hand trowel. Bulbs such as crocus, narcissus, and hyacinth are planted in the fall, while dahlia, amaryllis, gladiolus, and similar bulbs are planted in the spring.

Each type of bulb has a recommended planting depth and spacing. As a general rule, bulbs should be planted the same distance apart as their planting depth (see Figure 19-5).



Bulbs should be fertilized by adding a small amount of fertilizer (5-10-5) to the bottom of the bed and covering it with soil before planting the bulb. Just before growth starts each spring, bulbs should receive a light application of a complete fertilizer, for example 5 pounds of 5-10-5 for every 100 square feet of bed area.

Care After Flowering

Bulbs flowering in the spring should be dug up after the foliage turns yellow and dies. Some bulbs such as tulips and hyacinths need to be dug every year and replanted for high-quality flowers. Other bulbs such as daffodil, crocus, lily, and colchicum need to be dug up only every three to five years, thinned, and replanted. Digging the bulbs after all the foliage dies and no green remains in the foliage ensures that the bulb completed its growth cycle and all the food is stored in the bulb.

Dusting the bulbs with a pesticide prevents insects and rodents from attacking bulbs during storage. Any bulbs showing signs of disease or damage are removed before storage. Bulbs are stored in peat moss or sawdust.

Bulb Pests and Diseases

Good cultural practices can control many of the pests. This includes such practices as weeding and keeping the bed free of trash so as not to provide a home for insects and disease organisms. Chemical control is also effective and necessary. Growers should seek expert advice before applying chemicals to bulbs. Table 19-6 lists the most common types of bulbs, pests, damage and control measures.

Forcing Bulbs

To enjoy the color and fragrance of flowering bulbs in the winter, bulbs can be forced. Forcing bulbs artificially breaks dormancy so they will flower when brought into a warm room. High-quality bulbs can be forced by potting them and storing them at 40[degrees] to 50[degrees]F for 10 to 12 weeks. Next, the potted bulbs are brought into a cool partially lit room. Bulbs then grow and bloom within 5 weeks after being taken from the cool storage. The process is challenging and provides plants for another market.

Flowering Houseplants

Indoor plants have added color and variety to many places of work and play for hundreds of years. To grow indoor plants successfully there are several factors to consider. These considerations are light, temperature, water/humidity, and general care. Of these factors, light and temperature are the most critical.


Light intensity and duration influence the growth and development of indoor plants. Too little light causes some indoor plants to grow tall and leggy and to lose leaves because the long, thin, weak stems cannot support the plant due to limited photosynthesis.

Five different categories describe the light requirements of indoor plants:

1. Full sun: at least 5 hours of direct sunlight per day

2. Some direct sun: brightly lit but less than 5 hours of direct sunlight

3. Bright indirect light: considerable light but no direct sunlight

4. Partial shade: indirect light of various intensities and durations

5. Shade: poorly lit and away from windows


Indoor plants survive best at constant temperatures. For optimum indoor growth, temperature should remain in a range from 60[degrees] to 68[degrees]F. Temperature in an area also interacts with light humidity and air circulation. Plants have various temperature requirements and should be placed in areas that match their requirements.


Water is essential. But water for indoor plants is not as much as many individuals assume. Many indoor plants die from overwatering. Like the requirements for light and temperature, each plant varies in its requirement for water. Without knowing the specific requirements, indoor plants should be watered when they are a little on the dry side.

Indoor plants are watered from the top, by soaking the pot in water, or by placing water in a second container at around the bottom of the pot. The water used should not be too hot or too cold. Besides water, plants need moisture in the air (relative humidity). Finally, good drainage is essential for potted indoor plants.

General Care

Under general care, plants need fertilizing on a regular basis for good health. A balanced fertilizer such as 5-5-5 should be applied at regular intervals. There are two types of fertilizers, slow release and soluble. With slow-release the plant absorbs the fertilizer as needed, which eliminates the possibility of overfeeding or fertilizer burn. The soluble fertilizer must be dissolved in water before applied. Be sure to read manufacturer's directions before applying as these fertilizers may also be concentrates. Do not fertilize when the plant is dormant or very dry. Flowering plants need more fertilizer. Groom a plant by dusting, collecting dead leaves, and loosening dirt. Misting can be done with mild dish washing soap and water to control insects.

After time, the root systems of potted plants become restricted by the pot or other container. This creates a condition called root-bound, and the plant must be repotted to stay healthy. In general, repotted plants are moved to a pot no more than 2 inches wider than the original. Flowering plants should be repotted after the flowers have faded. Repotting is also a time to check the health of the root system and remove any damaged or unhealthy roots.

The method chosen for propagation depends on the type of plant--herbaceous or woody, flowering or foliar. Both sexual and asexual methods of propagation are used. Chapters 4 and 5 cover the methods of plant propagation. Common asexual methods used with indoor plants include: leaf and stem cuttings, removal of plantlets, and air layering.

Common Flowering Indoor Plants

A few common indoor flowering plants are African violets, fuchsias, gardenias, geraniums, and impatiens. Some that grow outdoors as well as indoors are wax begonias, ageratums, verbenas, and petunias.

Commercial Greenhouse Environment

Three purposes of a greenhouse include:

1. Provide a controlled environment for plants grown on a large scale.

2. Grow plants in areas where outdoor growth during winter seasons is not possible.

3. Extend the growing season for plants that would normally go dormant (see Figure 19-6).


Basically, greenhouses are structures used to start and to grow plants year-round. It should be located to receive the maximum amount of sunlight. Further, greenhouses control temperature, moisture, ventilation and climate.

For optimal growth of plants, the temperature in greenhouses is controlled and monitored. Great variations in temperature cause fast vegetative growth or the lack of plant growth.

Plant growth in a greenhouse is also dependent on moisture (humidity). Moisture aids in helping plants maintain their shape and nutrient transport. Watering plants controls growth and helps maintain the humidity. The amount of water needed by plants depends on the type of plants and the conditions outside the greenhouse (see Figure 19-7).


Ventilation or the movement and exchange of air is important for optimum growth. Ventilation helps ensure the proper temperature and humidity in the greenhouse.

When considering a greenhouse, the climate of the area must also be considered. The climate will directly influence the structure, the heating and the cooling systems. Potential greenhouse growers should seek the best advice possible before construction or purchase of a greenhouse.

Greenhouse Features

Greenhouses can be constructed of several different types of materials, including: aluminum, iron, steel, concrete blocks, or wood. Materials used to cover the green house can be glass, soft plastic (polyethylene, vinyl or polyvinyl fluoride), fiberglass, shade fabric, acrylic rigid panels, or polycarbonate rigid panels. Some shapes for greenhouses are detached A-frame truss, quonset-style, and ridge and furrow. There are also cold frames, hotbeds, and lath houses. Types of greenhouse structures used for floriculture in recent years include: glass, fiberglass and other rigid plastic, plastic film, shade and temporary cover, and open ground (see Figure 19-8).



1. Flowering plants and foliage plants are grown for personal enjoyment and decoration.

2. These plants may be grown outdoors or indoors, and people grow their own or purchase these plants from nurseries and greenhouses.

3. Perennials have the advantage of regrowing year to year. While perennials do not require planting each year, they still require care.

4. Perennials require winter protection.

5. When gardeners or growers understand the features and characteristics of each type of flowering plant or foliage, they can combine plantings to give the best display of color.

6. Soil preparation, watering, and proper fertilization are necessary for flowering and foliage plants.

7. For the best results from annuals, growers should select hybrid seed. Some annuals do best when thinned after planting.

8. Watering methods need to be checked since some plants become susceptible to disease if sprinklers are used.

9. Bulbs are another way to produce flowering plants. Some bulbs are forced cold storage.

10. While many flowering and foliage plants are grown outdoors, many are produced in greenhouses. Here, the lighting, temperature, and watering can be closely controlled and different types of plants produced on a year-round basis. These are sold for resale and for home use indoors and outdoors.

Something to Think About

1. Name four common indoor flowering plants.

2. List four pests of bulbs.

3. What is the best pH range for flowering perennials?

4. How should bulbs be protected from insects, diseases, and rodents?

5. What is transplanting?

6. How are bulbs forced?

7. Why do people purchase flowering and foliage plants?

8. Describe a greenhouse environment.

9. Identify the features of a starting media.

10. Describe the time from planting to the time of sale for different types of plants.

Suggested Readings

Boodley, J. and S. E. Newman. 2008. The commercial greenhouse, 3rd Ed. Albany, NY: Cengage Delmar Publishers.

Dole, J. M. and J. L. Gibson. 2006. Cutting propagation: A guide to propagating and producing floriculture crops. Batavia, IL: Ball Publishing.

Griner, C. 2000. Floriculture design & merchandising. Albany, NY: Cengage Delmar Publishers.

Hamrick, D. Ed. 2003. Ball RedBook: Crop production (volume 2) 17th Ed. Batavia, IL: Ball Publishing.

Hamrick, D. Ed. 2003. Ball RedBook: Greenhouses & equipment (volume 2) 17th Ed. Batavia, IL: Ball Publishing.

Reader's Digest. 2003. Illustrated guide to gardening. Pleasantville, NY: The Reader's Digest Association, Inc.


Internet sites represent a vast resource of information. The URLs for Web sites can change. Using one of the search engines on the Internet, such as Google, Yahoo!,, and MSN Live Search, find more information by searching for these words or phrases: greenhouse production, floriculture, greenhouse construction, flower bulbs, annual flowers, potted plants, perennial flowers, indoor plants, and houseplants.
Table 19-1
Flowers and Foliage Use and Peak Seasons for Sales

Category         Crops                      Peak seasons

Personal and     Cut flowers and cut        Christmas, Valentine's
environmental    foliage or greens          Day, Easter, Mother's
adornment                                   Day, and Memorial Day

Personal         Flowering potted plants    Christmas, Easter, and
environment,                                  Mother's Day
intimate         Tropical foliage plants    Holidays and January
                 Hanging plants             Holidays, spring, and
                 Landscape plants,          Spring, fall
                 Patio container plants     Spring, fall

Personal         Bedding plants             Spring, fall
environment,     Woody ornamentals          Spring, fall
background       Herbaceous perennials      Fall, spring

Sustenance       Vegetable transplants      Spring, fall

Table 19-2
Time from Planting of Flowers to First Income

Crop                              Time to income

Cut flowers                       3-4 months
Potted flowering plants           3-4 months
Potted foliage plants (6 inch)    4-6 months
Woody plants in containers        3-18 months
Cut foliage                       1-2 years

Table 19-3
Temperature Requirements and Crop Examples

Crop requirements            Crop examples

Cool night temperatures      Cut flowers like carnations,
                             snapdragons, stock heather; flowering
                             potted plants like cyclamen, fuchsia,
                             tuberous begonia

Medium night temperatures    Cut flowers like roses

Warm night temperatures      Foliage plants

Cold winters                 Deciduous shrubs

Warm summers                 Ornamental plants like junipers

Table 19-4
Floriculture Crops- Top Five States by Value of Sales,
2006 for Operations with $100,000+ Sales

Commodity                Rank    ($1,000)        1            2
                                15 states        CA           FL

Total Value Wholesale           3,834,912    1,007,463    786,614
                                             26.3%        20.5%

                                15 states        CA           MI

Annual Bedding/           1     1,281,113    231,199      192,861
Garden Plants                   33.4%        18.0%        15.1%

                                15 states        CA           FL

Potted Flowering          2     619,925      205,990      79,791
Plants                          16.2%        33.2%        12.9%

                                15 states        FL           CA

Foliage Plants for        3     542,533      366,414      97,893
Indoor or Patio Use             14.2%        67.5%        18.0%

                                15 states        CA           FL

Cut Flowers & Cut         4     520,725      338,666      96,302
Cultivated Greens               13.6%        65.0%        18.5%

                                15 states        CA           SC

Potted Herbaceous         5     507,346      70,186       4-Oct
Perennial Plants                13.2%        13.8%        13.3%

                                15 states        FL           MI

Propagative               5     363,270      95,489       81,587
Floriculture Materials          9.5%         26.3%        22.5%

Commodity                           3            4            5
                                    MI           TX           NC

Total Value Wholesale           363,158      256,468      190,334
                                9.5%         6.7%         5.0%

                                    TX           FL           NC

Annual Bedding/                 156,058      118,776      108,712
Garden Plants                   12.2%        9.3%         8.5%

                                    NY           PA           NC

Potted Flowering                50,288       39,162       38,356
Plants                          8.1%         6.3%         6.2%

                                    TX           HI           IL

Foliage Plants for              19,301       15,254       7,600
Indoor or Patio Use             3.6%         2.8%         1.4%

                                    WA           HI           OR

Cut Flowers & Cut               20,088       18,051       15,306
Cultivated Greens               3.9%         3.6%         2.9%

                                    MI           NJ           OH

Potted Herbaceous               45,970       45,834       39,394
Perennial Plants                9.1%         9.0%         7.8%

                                    CA           WA           PA

Propagative                     63,529       26,017       20,673
Floriculture Materials          17.5%        7.2%         5.75%

Courtesy of USDA-NASS, July 2007.

Table 19-5
Various Flowering Perennials

                  When to                     Germination
Name              plant seed      Exposure    time (days)    Spacing

Achillea mille    Early spring    Sun             7-14         36"
folium (yarrow)   or late fall

Alyssum           Early spring    Sun            21-28         24"

Anchusa italica   Spring to       Partial        21-28         24"
(Alkanet)         September       shade

Anemone           Early spring    Sun              4         35"-42"
pulsatilla        or late all
(windflower)      for

Anthemis          Late spring     Sun            21-28         24"
tinctoria         outdoors
(golden Daisy)

Arabis alpine     Spring to       Light            5           12"
(rock cress)      September       shade

Armeria           Spring to       Sun              10          12"
maritima          September
(sea pink)

Aster alpinus     Early spring    Sun            14-21         36"
(hardy aster)

Astilbe           Early spring    Sun            14-21         24"
(false spirea)

Begonia           Summer in       Shade            12         9"-12"
evansiana         shady, moist
(hardy begonia)   spot

Bergenia          Late winter     Light            10          18"
purpurascens                      shade

Name               Height         Best use               Color

Achillea mille      24"      Borders, cut flowers     Yellow, white,
folium (yarrow)                                       red, pink

Alyssum            9"-12"    Rock garden, edging,     Yellow
saxatile                     cut flowers

Anchusa italica   48"-60"    Borders, background,     Blue
(Alkanet)                    cut flowers

Anemone             12"      Borders, rock garden,    Blue, rose,
pulsatilla                   potted plant,            scarlet
(windflower)                 cut flowers

Anthemis            24"      Borders, cut flowers     Yellow
(golden Daisy)

Arabis alpine      8"-12"    Edging, rock garden      White
(rock cress)

Armeria           18"-24"    Rock garden, edging,     Pink
maritima                     borders, cut flowers
(sea pink)

Aster alpinus     12"-60"    Rock garden, borders,    White
(hardy aster)                cut flowers

Astilbe           12"-36"    Borders                  Pink, red,
arendsii                                              white
(false spirea)

Begonia             12"      Flower bed               Yellow, pink,
evansiana                                             white
(hardy begonia)

Bergenia           2'-3'     Medicinal                Pink, red

Name                     Remarks

Achillea mille    Seed is small. Water with
folium (yarrow)   a mist. Easy to grow.

Alyssum           Blooms early spring. Good
saxatile          in dry and sandy soils.

Anchusa italica   Blooms June or July.
(Alkanet)         Refrigerate seed 72 hours
                  before sowing.

Anemone           Blooms May and June.
pulsatilla        Is not hardy north of
(windflower)      Washington, DC.

Anthemis          Blooms midsummer to
tinctoria         frost. Prefers dry or
(golden Daisy)    sandy soil.

Arabis alpine     Blooms early spring.
(rock cress)

Armeria           Blooms May and June.
maritima          Plant in dry sandy soil.
alpine            Shade until plants are
(sea pink)        well established.

Aster alpinus     Blooms June.
(hardy aster)

Astilbe           Blooms July and August.
arendsii          Gives masses of color.
(false spirea)

Begonia           Blooms late in summer.
evansiana         Can be propagated from
(hardy begonia)   bulblets in leaf axils.

Bergenia          Hummingbirds love it.

Courtesy of USDA.

Table 19-6
Common Bulb Pests and Diseases and Their Control

Host, pest, disease                             Damage


Spotted cutworm                   Feeds on flowers at night.

Bulb mites                        Rotting bulbs. See Hyacinth.

Narcissus bulb fly                Decaying bulbs. See Narcissus.

Leaf scorch, Red blotch           Reddish spots on flowers, leaves,
                                  bulb scales; stalks deformed.


Thrips                            Leaves silvered, flowers streaked,

Botrytis and other flower         Flowers, leaves, stalks spotted,
blights                           then blighted.

Corm rots, scab                   Lesions on corms, spots on leaves.

Yellows (due to a soil fungus)    Plants infected through roots,
                                  turn yellow and wilt.


Bulb mites                        Minute; less than 1/25 inch,
                                  white mites in rotting bulbs.

Aphids, several species           Leaves are curled; virus diseases
                                  may be transmitted.

Bulb nematode                     Dark rings in bulbs.

Soft rot                          Vile-smelling bacterial disease;
                                  often after mites.

                                            Iris (bulbous)

Tulip bulb aphid                  See Tulip.

Gladiolus, iris thrips            Leaves russeted or flecked,
                                  flowers speckled or distorted.

Leaf spot                         Light brown foliage spots
                                  with reddish borders.


Aphids (lily, bean, melon,        Curl leaves, transmit mosaic and
peach, other species)             other virus diseases.

Botrytis blight                   Oval tan spots on leaves,
                                  which turn black, droop.

Mosaic and other virus            Plants mottled, stunted.


Narcissus bulb fly                Fly resembling bumblebee lays eggs
                                  on leaves near ground in early
                                  summer. Larva, fat, yellow maggot
                                  1/2 to 3/4 inch long, tunnels in
                                  rotting bulb.

Bulb nematode                     Dark rings in bulb.

Basal rot                         Chocolate-colored dry rot at base
                                  of bulbs.

Smoulder (botrytis rot)           Rots the foliage and flowers in
                                  cold, wet seasons; leaves stick
                                  together when they emerge and
                                  infected bulbs rot in storage

Scorch                            Affected plant parts are often bent
                                  or deformed at the point of
                                  infection; brown spots or blotches
                                  with yellow borders develop.


Tulip bulb aphid                  Powdery white or grayish aphids
                                  common on stored bulbs.

Green peach, tulip leaf, and      Transmit viruses to growing plants.
other aphids

Botrytis blight, fire             Plants stunted, buds blasted,
                                  white patches on leaves,
                                  dark spots on white petals,
                                  white spots on colored petals,
                                  gray mold, general blighting.
                                  Small, shiny black sclerotia formed
                                  on petals, foliage rotting into
                                  soil and on bulbs.

Cucumber mosaic                   Yellow streaking or flecking of
Lily mottle viruses               foliage. Cause broken flower
                                  colors, mottled foliage, in tulips.

Host, pest, disease                             Control


Spotted cutworm                   Scatter cutworm bait or spray with

Bulb mites                        Discard soft bulbs.

Narcissus bulb fly                Discard soft bulbs.

Leaf scorch, Red blotch           Discard bulbs or remove diseased
                                  leaves. Avoid heavy watering.


Thrips                            Spray with lindane in spring.
                                  Dust corms before storing.

Botrytis and other flower         Spray with zineb
blights                           (Dithane Z-78 or Parzate).

Corm rots, scab                   Dust with Arasan before planting.

Yellows (due to a soil fungus)    Choose resistant varieties.


Bulb mites                        Discard infested bulbs.

Aphids, several species           Spray with malathion, rotenone, or

Bulb nematode                     Discard.

Soft rot                          Discard.

                                            Iris (bulbous)

Tulip bulb aphid                  See Tulip.

Gladiolus, iris thrips            Spray or dust with malathion or

Leaf spot                         Spray with zineb or bordeaux
                                  mixture; clean up old leaves.


Aphids (lily, bean, melon,        Spray with malathion, being sure
peach, other species)             to cover underside of leaves.

Botrytis blight                   Spray with bordeaux mixture.

Mosaic and other virus            Rogue infected plants. Start lilies
diseases                          from seed in isolated portion of


Narcissus bulb fly                Sprinkle naphthalene flakes around
                                  plants to prevent egg-laying.
                                  Before planting, dust trench with
                                  5% chlordane and dust over bulbs
                                  after setting.

Bulb nematode                     Discard bulbs. Commercial growers
                                  treat with hot water, adding
                                  formalin to prevent rot.

Basal rot                         Inspect bulbs before planting.

Smoulder (botrytis rot)           Remove diseased plants.
                                  Put new bulbs in new location.
                                  Applications of fungicides such as
                                  chlorothalonil, thiophanate-methyl,
                                  iprodione, and mancozeb when
                                  new growth emerges in the spring.

Scorch                            Minimize moisture on the leaves
                                  and flower stalks by careful
                                  watering; provide good ventilation
                                  and plenty of light; discard
                                  heavily infected bulbs.


Tulip bulb aphid                  Dust with 1% lindane before

Green peach, tulip leaf, and      Spray or dust with malathion or
other aphids                      lindane.

Botrytis blight, fire             Discard all infected bulbs.
                                  Plant new tulips in new location.
                                  Spray with ferbam or zineb,
                                  starting early spring. Remove
                                  flowers as they fade, remove all
                                  tops as they turn yellow.

Cucumber mosaic                   Do not grow near cucurbits or
Lily mottle viruses               gladiolus. Do not plant near
                                  lilies. Control aphids.

Courtesy of the Brooklyn Botanic Garden.
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Title Annotation:PART 5: Plants and Society
Publication:Fundamentals of Plant Science
Date:Jan 1, 2009
Previous Article:Chapter 18: Fruit and nut production.
Next Article:Chapter 20: Forage grasses and sod.

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