Cercis canadensis, Eastern Redbud – Ooh, La, La, Lovely
George Washington transplanted many eastern redbuds (Cercis canadensis) onto his property at Mount Vernon, Virginia. He loved their delicate color in the spring. When he began gardening, Washington chose mainly trees from Europe. Redbud was one of the native American trees that converted him to making Mount Vernon a showplace of American species.
Eastern redbud is a gem of a tree. Small, with graceful shape, it produces intense red-purple flowers, followed by big leaves that turn a rich yellow in the fall. And that’s just our native eastern redbud; there are dramatic horticultural varieties.
The genus Cercis has ten species, found across the Northern Hemisphere, in the pea family, Fabaceae. Two species are native to North America, the eastern redbud, Cercis canadensis and the California redbud, Cercis orbiculate. Eastern redbud’s native range is from Massachusetts to Florida, Wisconsin, Nebraska, New Mexico and into Mexico. The scientific name, Cercis canadensis is a bit misleading, since, although native to Canada, it is only found in southwestern Ontario; it is more widespread in the United States. California redbud is native to California, Arizona, Utah, and Nevada. Other species, such as the Chinese redbud, Cercis chinensis, have been introduced as garden plants. This article is about Cercis canadensis.
Cercis, usually pronounced sir-siss, is based on kerkis, the Greek word for a weaver’s shuttle. Individual seeds are flat and oval and were seen as resembling a weaver’s shuttle. This is one of the words in botany that refer to things that were familiar in 1750, for example weaving and blacksmithing tools, that are little known today.
The common name redbud describes the flowers, which look bud-like even when fully open. They can be very red. An old name for redbud is Judas tree, a carryover from Europe. The very similar European species, Cercis siliaquastrum, was believed to be the tree upon which Judas, the disciple who betrayed Jesus, hanged himself. In the myth, the Judas tree had white flowers, which turned red in shame. Cercis canadensis looks enough like C. siliaquastrum that settlers easily applied the European name to it. However, Americans have called C. canadensis redbud since at least 1700; let the European species have the name Judas tree.
Redbuds bloom in spring, February in the south, May in the north, before the tree—or other trees—leaf out. The flowers are bright magenta, small (about ¼”) pea-like blossoms. They appear in small clusters directly off the trunk and large branches, quite an unusual character. Usually numerous, they create a cloud of color at about eye-level. The pretty flowers are edible. They don’t have much taste, but are beautiful in a salad or dessert.
The leaves, three to six inches across and round to heart-shaped, expand as the flowers fade. Often, they start bronze, becoming medium green. In fall, they turn a gentle yellow. The trees produce two inch by ¼ inch, pea-like pods that contain several shuttle-like, hard seeds. The often reddish pods stay on the tree after the leaves fall and add winter interest.
Choosing a Redbud
Good Spots for Redbuds
Established redbuds are hard to move, so consider your site carefully. They like full sun, so need four—six is better—hours of sunlight, daily. If your summers are hot and dry, afternoon shade is important. In northern areas, protect the tree from the worst winds and cold of winter. The site will shape the tree. Alone in full sun, trees are compact and symmetrical, in partial shade more open and delicate. Redbuds prefer light sandy soils but can grow well in dense clay soils; they do not tolerate soggy soils.
Use redbuds as a bit of spring interest, or mass them for a burst of color. They are called forest understory trees, but they actually grow at forest edges, places with those six hours of full sun. They grow well and look great in mixed stands, among pines and oaks, for example. Redbuds are short-lived, beautiful for twenty years, then declining. Of course, you can just replace the aging tree, but you could also plan for aging, creating a spot where about every ten years you add a younger tree to fill in as the older ones age.
Redbud flower colors draw attention rather than blend. When my cherry tree puts out its pale orangy flowers at the same time, I don’t care for the combination, so I recommend considering what colors are near your redbud. Some years, the cherry is slow to flower and the redbud looks absolutely magnificent against the Colorado blue spruce. Redbuds will flower for three weeks if the weather is good.
Give the tree you are planting room to grow to full size. They grow relatively fast. My tree was a seedling, three inches tall, 15 years ago. It is now a handsome 15-foot tree, its canopy ten feet wide.
Transplanting a Redbud
Planting in early spring is recommended, but you can also plant redbuds in fall, once the temperatures cool. Smaller trees are easier to handle and will catch up with larger ones in a couple of years because they more quickly become established.
Dig a hole one and one-half times the size of the roots on your tree. You want the roots to reach undisturbed soil quickly. Cut any roots that encircle the root ball and open the root ball, so there is space between the roots. In the hole, keep the spot where the roots flare out from the trunk just above the soil surface. Refill the hole with soil and tamp down lightly. Skip amendments like compost or fertilizer as they slow the expansion of the roots by making it too easy to find nutrients close by. Newly planted redbuds need an inch of water, weekly, the first year, but be sure not to leave the tree in saturated soil.
Propagating Redbuds
Redbuds can be grown from seeds, but that requires both scraping (scarification) and a cold treatment of about 60 days. You can plant seeds outside in the fall, but germination is not very predictable. Simpler is to find seedlings and move them. Seedlings from horticultural varieties may differ a lot from their parent tree, however. Trees from seeds may bloom in four years. Redbuds can also be rooted from cuttings, bare root plants, and 2-gallon pots.
Redbud Care
Established redbuds need little attention. Provide mulch to retain moisture and reduce weeds, but to limit disease, leave space around the trunk; make a mulch doughnut. If needed, prune when the tree is dormant.
Sunscald, Wilts, and Insects
The best defense against the problems of redbuds is a healthy tree that will out-grow them. Aid that by buying sunscald- and canker-resistant, locally-adapted varieties.
Redbuds can develop bark damage from strong sunlight, called sunscald. Minor sunscalding heals on its own. Watch, though, that sunscald wounds do not become infected by fungi or bacteria. Shading the tree to the south and west or covering the trunk with tree wrap, especially in winter, can prevent sunscald.
Wilted leaves can be caused by canker or verticillium wilt. Canker is due to several different bacteria or fungi, while verticillium wilt is a particular fungal disease. Getting these diseases usually indicates a stressed tree—too much water, not enough water, extreme heat, extreme cold. If the stress is removed, trees often recover on their own. Get expert identification before treating wilt, rather than treat for the wrong cause.
Well-adapted to North America, many insects eat redbud leaves, wood, and seeds. This is a good thing. Birds in North America have dropped 30% since 1970; loss of food for their young was a big part of it. The insects that munch redbud leaves feed nesting chicadees, cardinals, warblers and more; birds will be attracted to your tree. The butterfly, moth, and wood-borer larvae that eat redbud leaves and wood do little damage. Occasionally webworm moth caterpillars (Hyphantria cunea) defoliate a redbud in late summer. This looks dreadful, but the tree almost always recovers, and the local birds had a feast. Wood-boring beetles are not a serious problem unless the tree is old or unhealthy. Leaf-cutting bees (family Megachilidae) cut ¼” inch holes for their nests, like someone took a hole-punch to the leaf. They only need tissue from a few leaves; watch for these important native pollinators. Redbuds tolerate browsing by deer.
Redbuds are a delight all year long.
