Tidewater Gardening April 2006 - K. Marc Teffeau

Radiant Redbuds

   As you drive down the road in early to mid April, you will see pockets of bright reddish purple color in the woodlands. This spectacular color display comes from the Eastern redbud (Cercis canadensis), a small, short-lived deciduous tree found throughout the eastern United States.
    This member of the legume family lights up our area woodland edges in April with its rose-colored (rarely white) flowers. Redbuds are often seen blooming the same time as the Flowering Dogwood, which makes a spectacular show.
    The Redbud is also known as Judas-tree. According to legend, Judas Iscariot hanged himself from a branch of the European species Cercis siliquastrum.
    Eastern redbud is a strikingly conspicuous tree in the spring because it flowers before other tree leaves form. Redbuds are an understory tree. They are adapted to live under the canopy of the larger trees in a forest. They are usually less than 20 feet tall, although they can get up to 50 feet when growing in the open.
    The flowers of the Redbud have a typical pea-blossom construction. The flowers then produce green seed pods. As they mature, the pods become brown and papery. They may persist on the branches until the following spring.
    The broad 4”x4” ovate (heart-shaped_ leaves of the Redbud are distinctive. They emerge as bronzed to medium-green in color, slowly turning to dark green. They grow in an alternate pattern on the twigs. The fall color of the foliage is often chartreuse to yellow, but doesn’t stand out.
    The bark of the Redbud is gray and smooth in young trees. It becomes reddish-brown with flattened scaly plates in older specimens.
    The Redbud has an upright vased-shaped growth habit in youth (if grown in a open area), spreading to a rounded irregular shape with age; however, it is often found with an irregular shape at the edges of forests and woodlands, as it stretches towards the limited sunlight. It is found both as a single-trunked and multi-trunked tree and has a rapid growth rate in youth, but medium growth rate after ten years.
    The Redbud is great as a single specimen, in a group, in a shrub border, and especially nice in woodland and naturalized type landscapes. It does best in full sun to partial shade and prefers and needs a moist, rich, well-drained soil, but is somewhat adaptable to many types of soils, soil pHs, dry soils, and other moderately stressful situations (except wet sites, which make it more prone to Verticillium wilt).
    Unfortunately, it does have several disease problems, most prominently trunk canker, which causes individual branches or sections of the tree to die and often leads to an overall decline, often followed by heartwood rot. Verticillium wilt also leads to canopy dieback and often a slow death of the tree. Insect-wise, scale insects are a fairly common pest problem.
    Even with its potential problems, the Redbud is still recommended as a desirable tree to plant in the home landscape. It can be planted as a single specimen tree or used effectively with the white-flowering variety Cercis canadensis Alba for a striking floral contrast.
    Redbud also lend themselves as the first (or second) of a series of flowering ornamental trees in combination with other native Eastern Shore trees like the Serviceberry (Amelanchier), Flowering Dogwood (Cornus florida) and with Carolina Silverbell (Halesai carolina), Crabapple (Malus), Chinese Dogwood (Cornus Kousa), and Japanese Tree Lilac (Syringa reticulata) for a floral sequence of ornamental trees with white, cream, or lavender/pink/red flowers in spring and early summer.
    There are a couple of notable cultivars of Redbud that are available in the nursery trade. Cercis canadensis, ‘Forest pansy,’ is known for its new foliage that emerges red-purple, becoming bronzed to dark green in summer, with darker lavender flowers in spring. ‘Covey,’ also known as Lavender Twist™, is a weeping form of this tree.
   ‘Hearts of Gold’ is a good selection and unique because its emerging leaves have a copper tint which changes to a brilliant gold. It maintains its gold foliage color in the full sun but in the shade it changes to green. Because it is unique however, this cultivar is hard to find in the nursery trade. If you are looking for a true ‘red’ colored Redbud the ‘Appalachian Red’ is the closest to a red-colored flower tree that you can find. A true pink , and a very heavy flower producer is ‘Tennessee Pink.’
    The native Eastern Redbud has a Chinese relative that exhibits all the nice flowering and growth characteristics of the Eastern but without the disease problems. The Chinese Redbud, C. chinensis, has been around for a long time and is a good substitute for the native species. It usually grows as a smaller, multi-stemmed tree as compared to C. canadensis.
    Two common cultivars that are found in the nursery trade are ‘Avondale’ and ‘Don Egolf.’ ‘Avondale’ shows very deep pink flowers held in dense clusters around the stem. ‘Don Egolf’ is a U.S. National Arboretum release which exhibits limited seed production and a compact habit. So, whether you choose the native Eastern Redbud, or its oriental cousin, the Chinese Redbud, consider using these trees in the landscape to bring bright spring color.
    While you are busy dodging the proverbial April showers, there is lots to do in the landscape. Observe you daffodil and other spring bulbs while in bloom this spring to be sure they have not been shaded by the new growth of other tree or shrub plantings. If they have, you may need to move the bulbs to a new, sunny location or prune back the plantings. Label the clumps of daffodils that are too crowded, as overcrowding inhibits blooming. Dig up and separate in July.
    Cut flower stalks back tot he ground on daffodils, hyacinths and other spring flowering bulbs as the flowers fade. Do not cut the foliage until it dies naturally. The leaves are necessary to produce strong bulbs capable of reflowering. To keep the planting going you can fertilize bulbs upon emergence of foliage with a 10-10-10 fertilizer, using a rate of 1 to 3 pounds per 100 square feet. Repeat the application after the bulbs have bloomed.
    If we have warm weather in April, we might be looking at planting annuals in the landscape a week or two earlier than normal. When purchasing bedding annuals this spring, choose properly grown plants with good color. Buy pants with well developed root systems that are vigorous, but not too large for their pots. Also, when you are out shopping for annual flowers for your garden, look for plants with lots of unopened buds. Plants that bloom in the pack are often root-bound and can be set back for several weeks after being transplanted. Plants not yet in bloom will actually bloom sooner, be better established and grow faster.
    Chrysanthemums pop up in the flowerbed in April. Lift, divide, and replant them as soon as new shoots appear. Each rooted shoot or clump will develop into a fine plant for late summer bloom. Pinch out the top when the plants are about 4 inches high to thicken the plant. You can also take chrysanthemum cuttings not through mid-June for flowers during fall and winter in the greenhouse.
    Now is also the time to do some planning and planting of perennial flowerbeds. One way to increase the apparent length of your flower borders when seen from inside, is to place the majority of the warm- and hot-colored perennial plants (yellows, oranges and reds) nearest the house. Concentrate the blues, which have a tendency to appear more distant, in the second half of the garden. Along with the blues, include some pink and mauve flowers.
    Plants with silver foliage can be used to provide a unifying ground color throughout. The actual dimensions of the borders and the paths separating them can help increase the illusion of distance. In a 20-foot-long border, make the planting about 1½ feet narrower and the path about 1 foot narrower at the end away from the house.
    If you would like to attract hummingbirds to the flower border this year, plant red or orange flowers. Monrada (beebalm) is a good perennial to provide nectar for these small birds.
    April is also a good time to scatter annual poppy seeds in flower borders. The fine seeds need no covering. The plants grow rapidly and provide colorful flowers in early summer.
    For hot-weather color in the flower bed, consider one of the following: Gloriosa Daisy, Madagascar Periwinkle, Ornamental Peppers, Mexican Zinnia or Amaranthus ‘Joseph’s Coat.’ Plant after all danger of frost is past and plan for color until winter arrives.
    Late April is a good time to plant dahlia tubers in the flowerbed. If you dug up and stored dahlia tubers over this winter you can determine if they survived storage by sprouting them indoors in a warm, lit spot. Fill the bare spots in the flowerbed with moss roses Portulaca and feed regularly to encourage blooms into the summer.
    Happy Gardening!!!