Columbines and their insect pests.
The graceful lacy leaves of the aquilegia (ack-will-EE-gee-ah) are held onto the plant by thin delicate stems, so that the leaves dance softly in a breeze. The leaves of the columbine are generally green but some show a bluish tinge or a grayish hue. These plants form a beautiful mounding display of leaves that are further enhanced by the addition of the bloom.
The beauty of this plant is in the flower. Every spring I cannot wait for the aquilegia plants that are over-wintered in our greenhouses to bloom. Not only are these plants larger but the show of flowers are phenomenal. The blooms of these hybrid varieties are made of two parts. The first part is the outer, 5-petal, cup-like form (the sepal) that narrows and holds the inner true petals. The inner petals may be long or short. In addition to single-coloured flowers, bi-color combinations of blues, purple/whites, red/yellows, pink/white, are common.
Plants of the columbine family vary in height, flower size and colour. Hybrid varieties allow you to plant columbines in all areas of the garden. They will grow in either full sun or dappled shade in a well-drained garden bed. If you prefer more bloom on the plant make sure to place it in a sunnier location. Columbines bloom May to June. To promote a longer blooming period, deadhead the spent blooms. When the plant has finished its season, the leaves will slowly yellow. By midsummer you can remove unsightly foliage and wait for the arrival of new growth when the temperatures cool.
The native columbine species are short-lived perennials with a stout fibrous taproot, and leaves arising at or near the stem base. Three species of wild columbine occur in the prairie region and may be grown in gardens. The Canada or wild columbine, Aquilegia canadensis, is fairly common in the boreal forest from southern Manitoba to eastern Saskatchewan. The flowers are borne on a stalk, 30-80 cm (12-31 in) tall, and the flowers are various shades of red and yellow. The blue or small-flowered columbine, A. brevistyla, occurs in open woods, meadows, and rocky slopes across the region, but is less common in the south and east. The flower stalk is 20-50 cm (8-20 in) tall and carries 2-3 flowers, blue and cream in colour, with 5 bluish hooked spurs. Gardeners in western Alberta also may grow A. formosa, a western species that resembles A. canadensis.
In addition, a European columbine, Aquilegia vulgaris, has escaped from gardens. In eastern North America it now grows wild as far west as Thunder Bay, ON, The flowers are blue, purple, pink, or white, with short, thick, strongly-recurved spurs On the prairies, apparently feral European columbines with both pink and blue-flowered plants, have appeared in gardens in Winnipeg and in a farmstead near Indian Head SK. It is probable that local escaped populations occur scattered across the moister parts of the prairies.
In addition to the native species, the prairie gardener can grow a wide variety of cultivars, selections and hybrids. The flowers of the horticultural varieties that have been bred from the native Aquilegia canadensis ('Songbird' series, 'Mckana' hybrids) are long-spurred, whereas those bred from the European A. vulgaris (Nora Barlow, Ruby Port) have short, strongly-recurved spurs.
Columbines come both in species varieties and hybrid forms. When they are in bloom, they are a plant hard to resist. Interesting columbines, derived from the North American species, that are available at the garden centers include: Aquilegia hybrid nana (Winky varieties)--50 cm (20 in) high plants with upward facing blooms suitable for pots or garden.
F1 Songbird series--ranging from 30-60 cm (12-24 in). Free-flowering plants suitable for pots or garden. The varieties have a wide variety of flower colours, and the colours are slow to fade. Songbird 'Dove' is my favorite of these. It is completely white, and adds to a cool shade garden with white flowering plants such as variegated Hostas, Hosta 'Blue Cadet', Lamium 'white Nancy' and ferns.
McKana hybrid mix--plants 1 m tall with long-spurred large blooms, various colours including white and pink;
Dragonfly mix--45 cm (18 in) tall, blooms later than the songbird varieties;
Biedermeire mix--35 cm (14 in) tall, flowers have short spurs and a variety of colours is available.
Red Hobbit--up to 40 cm tall, flowers red and white, long-spurred, and ruffed or wrinkled.
Varieties from the European A. vulgaris that are hardy on the prairies include:
Nora Barlow--var. stellata, very tall, with double, dark pink with white picotee, spurless flowers;
Ruby Port--tall, with bright, burgundy-coloured, spurless flowers;
Lime Frost--flowers purplish-blue with white dusting and white-tipped petals. Leaves variegated.
In western Canada, growing columbines is both easy and frustrating. They are prolific seeders, which makes up for their relatively short life spans (about 3 winters). The plant itself may 'disappear' (due to poor drainage, rabbit damage, columbine borer, too little or too much snow or some unknown reason). This happened to my beloved 'Nora Barlow.' I thought I had the best location. 'Nora' grew beautifully for about 3 years and I was sad that she did not return one spring. As an avid gardener, I could not see a space left unplanted. That year I filled in the spot with annuals. The very next year, I was delighted to see many little "Nora's" beginning to grow. The seed from the mother plant had stayed dormant for a year. Young seedlings can be moved easily, but older columbine plants do not take kindly to being moved. They have long taproots that like to take hold. Different varieties may cross-pollinate, giving rise to new types that you may choose to keep or rogue out of the flower bed.
Insect pests can shorten the life span of your plants, and you can expect to see the following:
Two species of columbine leaf miner, Phytomyza aquilegivora and P. aquilegiana, are the most common, and least serious, type of insect injury to columbines (see damage in picture below--photo Bill Turnock). The larvae of these flies feed within the leaves, making tortuous tunnels that are pale against the green leaf.
They do not affect the growth or flowering of the plant, and all types of columbine are more or less susceptible to attack. Some gardeners tolerate their presence, regarding the mines as decorative, or at least innocuous. This is a sensible reaction, since there are no recommended chemical controls for them. Other gardeners hate to see the green leaves disfigured. Since chemical controls are not effective, you can kill the larvae by pinching the end of the tunnel between thumb and finger. The earlier you pinch the tunnel, the more likely you are to kill the larvae. Infected leaves can be removed and destroyed, but this can reduce the vigour of the plant.
The columbine borer, Papaipema purpurifascia, will kill the plant it attacks if it reaches the root crown. A larva will tunnel down the centre of a flower stalk from just below the inflorescence to the root crown. The first sign of the presence of a larva in a stem may be the wilting of leaves and flowers, but in thick, vigourous stalks, the only evidence of attack is a purplish discolouration of the stem. When a larva burrows down to the base of the flower stalk, it will feed on the root crown, the leaves wither, and the plant dies. In my garden, in 2007, all of the wilted stems had larval tunnels, but half of the larva had died after they began tunnelling. When thicker stems are attacked, wilting may not occur, but an area of discolouration will be seen on the stem. At the first sign of the presence of a larva, you should cut off the infected stem just above the root crown, split it open, and kill the larva in the tunnel. If you are slow in cutting off the stem, the larva may be in the root crown (picture above--photo V.A. Dyck), but also may have completed feeding and left to pupate in the soil. The larva looks like a climbing cutworm and moths resemble the cutworm moths, often called miller moths, that come to lights in the autumn. Searching the soil to a depth of about 3 cm (1 in) within a radius of about 15 cm (6 in) from the plant will often reveal a fully-grown larva or a pupa (picture at right--photo V. A. Dyck), which can be destroyed. Chemical sprays are ineffective because the larvae are protected by the stem.
The larvae of the columbine sawfly, Pristiphora aquilegiae, are small, and their green colour blends beautifully with the columbine foliage. This pest overwinters as a cocoon in the soil. The adults emerge in the spring, mate, and the females lay batches of eggs in the crowns of individual plants. The larvae hatch and feed on the leaves. Since 20 or more larvae can hatch from a single batch of eggs, a plant can be completely defoliated in a couple of days. Control measures must be taken when the larvae are young. Insecticides recommended for leaf-eating insects will be effective if used according to directions. You may also remove the larvae from the plants and kill them. This insect was introduced from Europe. The first record of its occurrence in North America was from Ottawa in 1963, and it is common in eastern Ontario and Quebec. On the prairies it has been reported from Calgary and Edmonton, Alberta, Prince Albert, Saskatchewan, and the area around Winnipeg, Manitoba. It probably occurs across the entire region, but is not seen because of inconspicuous larvae and the preference of the adults for laying eggs on plants that are crowded and shaded. Gardeners who allow their columbines to seed in are more likely to harbour this pest, which can take out some young plants almost overnight, and seemingly disappear. Occasionally, a single, specimen plant is attacked, but the plant can replace the leaves that are eaten.
Try growing a columbine in your garden this year. Whether you get a plant or decide to scatter a few seeds, you will enjoy the delicate foliage and graceful flowers.
Carla Hrycyna is a new co-owner/president of St. Mary's Nursery & GardenCentre. She was the Greenhouse/Giftware Manager there for the past 12 years. Bill Turnock describes himself as a retired research entomologist who is still interested in insects, gardening, and a bunch of other things.
|Printer friendly Cite/link Email Feedback|
|Author:||Hrycyna, Carla; Turnock, Bill|
|Date:||Jan 1, 2008|
|Previous Article:||An open letter to Betty Biddulph.|
|Next Article:||Growing hydrangeas on the prairies.|