Eastern Redbud is a small deciduous tree with a short trunk, widely branched with spreading branches, growing to 30 to 40 feet high (but much shorter in Minnesota) with a rounded crown. Trunk branches are often found twisted on specimens not forced to grow straight as a young tree. It can also grow as a multi-stemmed large shrub.
The bark is initially dark gray to brown, smooth, becoming furrowed into scaly plates when older. Twigs are dark reddish-brown, slender with a few to many light colored lenticels. Flower buds have very dark, almost black scales. Leaf buds are small and round and mostly hidden.
The leaves are alternate, simple, long and broad, 3 to 5 inches long, heart shaped, with a broad but short pointed tip and smooth margins. There are 5 to 9 main veins, mid-green above and paler under with whitish hair. The leaf stalks are swollen on both ends with a pair of ovoid stipules at the base end. Fall color is yellow. Leaves appear after the flowers have opened.
The inflorescence is a cluster of 4 to 8 stalked flowers appearing along the branches of the previous years wood and before the leaves.
The flowers are pea type with 5 pink petals. The standard (or banner) is upright and smaller than the two laterals that are unusually placed in a backward ascending position behind the banner. These three are a lighter shade of pink. The two keel petals are darker pink - contrary to many pea species where the keel is the lightest color. These project forward and are closed so that the sexual parts can not initially be seen, but when mature, all the petals relax and the reproductive parts may be seen. Stamens number 10 and are in two rows, one row shorter than the other. The style is incurved. The calyx is a deeper shade of pink and does not have pronounced lobes. Some plants may have flowers that are more whitish than pinkish. Each flower is about 1/2 inch long.
Seed: Fertile flowers form a flattened oblong seed pod, pointed at the ends, pink initially and turning blackish in the fall. This splits open on one edge to reveal 4 to 10 flat, elliptical dark brown bean-like seeds. Pods are 2 to 4 inches long. This pod more closely resembles the domestic garden pea pod than the pods of most Pea family trees.
Habitat: Eastern Redbud grows best in moist soils of valley slopes and hardwood forests. In the home landscape it should be positioned to have moist to moderately moist well drained soils with sun at least 3/4ths of the day. Water it during dry periods and mulch the root zone but not the trunk. It does not tolerate transplanting very well. Redbud will grow in Minnesota but Minnesotans are advised to buy the "Minnesota Strain Redbud" adapted cultivar which has been available now for a number of years.
Names: The genus name Cercis is somewhat convoluted. It is derived from the Greek kerkis, which is a European species thought to be a poplar but was also confusing applied to Cercis siliquastrum, known as the Judas-tree, traditionally believed to be the tree Judas of Judaea hanged himself on. This use of Cercis, is why the Redbud is sometimes also called American Judas-tree. The species, canadensis, means 'of Canada' which is where it was probably first collected, but strangely enough, it is known in the wild only in SW Ontario and there it is uncommon. The author name of the plant classification, 'L.' refers to Carl Linnaeus (1707-1778), Swedish botanist and the developer of the binomial nomenclature of modern taxonomy.
Above: A Redbud growing in shrub form. 2nd photo - The masses of pinkish flowers appear before the leaves start to break bud. Here new leaves are just opening.
Below: Flower buds, covered with black scales, appear at the leaf scares along the old wood. Leaf buds are hidden. Twigs have conspicuous white lenticels.
Below: 1st photo - flower buds just breaking open. 2nd photo - Flowers of the the cluster fully developed. Note the flowers have the typical structure of the pea family except that the two lateral petals are in an ascending position behind the banner petal and the three are a lighter color than the keel.
Below: The calyx is of darker pink color without pronounced lobes. In the 2nd photo the stamens and style can be seen enclosed by the two keel petals.
Below: 1st photo - a small tree trained initially to grow upright. 2nd photo - the bark of a young tree beginning to show the fissures that with old age will create scaly plates. 3rd photo - A pair of stipules are at the end of the leaf stalk.
Below: The leaves are heart shaped, up to 5 inches long, smooth and medium green on top, paler color under due to many fine whitish hairs
Below: Developing seed pods - these resemble the pod of the garden pea.
Below: An example of an older tree that was allowed to grow without restrictions.
Below: The Redbud at Eloise Butler, on the hillside between the Upland and Woodland Gardens.
Notes: Eloise Butler introduced Redbud to the Garden in 1909 with plants provided by the Park Board Nursery which grew them at that time. Eastern Rosebud is not native to Minnesota. Martha Crone planted the tree four times in 1948, '50, '54, and '56. In North America it is found in the eastern half of the U.S. from Nebraska south to Texas then east to the coast, excluding only Minnesota and New England. In Canada it is known in Ontario. Cary George replanted the species in 1989 after the surviving tree in the Garden died from the drought of 1988.
Uses: Eastern Rosebud is used strictly as an ornamental and for that purpose it is a sight of beauty in the spring and handsomely leafed the rest of the season.
References: Plant characteristics are generally from sources 1A, 32, W2, W3, W7 & W8 plus others as specifically applied. Distribution principally from W1, W2 and 28C. Planting history generally from 1, 4 & 4a. Other sources by specific reference. See Reference List for details.
Identification booklet for most of the flowering forbs and small flowering shrubs of the Eloise Butler Wildflower Garden. Details Here.
Friends of the Wild Flower Garden, Inc. Text and photos are by G. D. Bebeau unless otherwise credited. "www.friendsofthewildflowergarden.org"