Commonly called Eastern redbud, Cercis canadensis grows in woodlands and woodland margins. With similar growing requirements as its Mediterranean cousin, the Judas tree (C. siliquastrum) and its California cousin (C. occidentalis), Cercis canadensis thrives in deep, fertile, well-drained soil in U.S. Department of Agriculture plant hardiness zones 5 to 9. Although native to woodlands in North America, Cercis canadensis tolerates full sun to dappled shade conditions. Plant in its final location when young, as Cercis canadensis does not transplant well.
Cercis canadensis grows in deep, moist gritty soil that drains well. Sow seeds two-tenths of an inch deep, set out rooted cuttings or plant a container-grown tree that is still very young. Bareroot and balled-and-burlap-covered trees are also available through nurseries. Deep soil is important as Cercis canadensis grows a long taproot within the first three years after propagation under normal growing conditions. Trees that grow taproots in woodland settings often grow only lateral roots when transplanted into a lawn.
Young Cercis canadensis trees benefit from shade, but as the trees mature, they perform best in full sun. In nature, Cercis canadensis is generally more numerous on south-facing slopes where the trees receive more sunlight than on northern exposures. Plant a young Cercis canadensis tree in a mixed border to provide beneficial shade from shrubbery while the tree is young; but as the tree grows taller than nearby bushes, it can receive more sunlight.
As a woodland tree, Cercis canadensis grows without heavy fertilization in a well-drained moist soil where it fixes its own nitrogen. Cercis canadensis adapts to many types of soil conditions, as long as the soil is not prone to flooding or bogginess. Tolerant of dry spells, Cercis canadensis can survive, but looks better when irrigated during summer drought. Optimum soil pH is 7.5 or higher. Fertilize with well-rotted or composted manure and mulch to compensate for loss of wood after pruning.
Prune Cercis canadensis to develop a strong structure. In late winter or early spring remove wayward branches or branches that cross each other. Cercis canadensis blooms on previous year's wood. Light pruning is generally all that is needed for single-trunk trees. A recent cultivar with purple-red leaves, "Forest Pansy," is often multi-trunked, and can be pruned back to two or three buds at the base in early spring to promote vigorous growth for colorful stems.
Bloom period for Cercis canadensis is March to May. Heavier bloom is produced when the tree experiences a chill period of at least 30 days of temperatures below 50-degrees Fahrenheit.
- United States Department of Agriculture Natural Resources Conservation Service: Eastern Redbud
- The American Horticultural Society A to Z Encyclopedia of Garden Plants; Christopher Brickell and Judith D. Zuk
- North Carolina State University: Tree Anatomy
- Auburn University: Cercis Canadensis
- University of Florida Extension: Cercis Canadensis "Forest Pansy"
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