Introduction

The state tree of Oklahoma, Eastern Redbud is a moderate to rapid-grower when young, reaching a height of 20 to 30 feet. `Flame' Eastern Redbud shows double pink flowers all over the tree in spring, just before the leaves emerge. Thirty-year-old specimens are rare but they probably can reach 35 feet in height forming a rounded vase. The pink flowers are displayed later than the species and are sterile so there is no fruit set. `Flame' Eastern Redbud has an irregular growth habit and is more upright than the species when young but forms a graceful flat-topped vase-shape or globe as it gets older. The tree usually branches low on the trunk, and if left intact forms a graceful multitrunked habit. Be sure to avoid weak forks by pruning to reduce the size of lateral branches and save those which form a `U'-shaped crotch, not a `V'. Keep them less than half the diameter of the main trunk to increase longevity of the tree. Do not allow multiple trunks to grow with tight crotches, instead space branches about 6 to 10 inches apart along a main trunk. Yellow (although somewhat variable and unreliable) fall color and tolerance to partial shade make this a suitable, attractive tree for understory or specimen planting. Best not used as a street tree due to low disease resistance and short life, but is nice in commercial and residential landscapes. Plant in a shrub border for a spring and fall color display.

General Information

Scientific name: Cercis canadensis

Pronunciation: SER-sis kan-uh-DEN-sis

Common name(s): 'Flame' Eastern Redbud

Family: Leguminosae

USDA hardiness zones: 4B through 9A (Fig. 2)

Origin: native to North America

Invasive potential: little invasive potential

Uses: container or planter; tree lawn 3-4 feet wide; tree lawn 4-6 feet wide; tree lawn > 6 ft wide; street without sidewalk; sidewalk cutout (tree pit); parking lot island < 100 sq ft; parking lot island 100-200 sq ft; parking lot island > 200 sq ft; deck or patio; shade; specimen; reclamation; highway median

Availability: not native to North America

Description

Height: 20 to 30 feet

Spread: 15 to 25 feet

Crown uniformity: irregular

Crown shape: vase, round

Crown density: moderate

Growth rate: fast

Texture: coarse

Foliage

Leaf arrangement: alternate (Fig. 3)

Leaf type: simple

Leaf margin: entire

Leaf shape: ovate, orbiculate

Leaf venation: palmate, reticulate, brachidodrome, pinnate

Leaf type and persistence: deciduous

Leaf blade length: 2 to 4 inches, 4 to 8 inches

Leaf color: green

Fall color: yellow

Fall characteristic: showy

Flower

Flower color: pink, lavender, purple

Flower characteristics: very showy

Fruit

Fruit shape: no fruit

Fruit length: no fruit

Fruit covering: no fruit

Fruit color: no fruit

Fruit characteristics: no fruit

Trunk and Branches

Trunk/bark/branches: branches droop; not showy; typically multi-trunked; thorns

Pruning requirement: needed for strong structure

Breakage: susceptible to breakage

Current year twig color: brown

Current year twig thickness: medium

Wood specific gravity: unknown

Culture

Light requirement: full sun, partial sun or partial shade

Soil tolerances: sand; loam; clay; acidic; alkaline; occasionally wet; well-drained

Drought tolerance: high

Aerosol salt tolerance: none

Other

Roots: not a problem

Winter interest: no

Outstanding tree: no

Ozone sensitivity: unknown

Verticillium wilt susceptibility: susceptible

Pest resistance: low resistance to pests/diseases

Use and Management

Eastern Redbuds grow well in full sun in the northern part of its range but will benefit from some shade in the southern zones, particularly in the lower mid-west where summers are hot. Best growth occurs in a light, rich, moist soil but adapts well to a variety of soil including sandy or alkaline. Trees look better when they receive some irrigation in summer dry spells. Its native habitat ranges from stream bank to dry ridge, demonstrating its adaptability. Trees are sold as single or multistemmed. Young trees are easiest to transplant and survive best when planted in the spring or fall. Containerized trees can be planted anytime. The beans provide food for some birds. Trees are short-lived but provide a wonderful show in the spring and fall.

Several other cultivars of Eastern Redbud may be seen: `Pink Charm' - flowers pink; `Pinkbud' - flowers pink; `Purple Leaf' - young foliage purple; `Forest Pansy' is a particularly attractive cultivar with purple-red leaves in the spring, but color fades to green in the summer in the south. Cercis canadensis var. texensis `Texas White' and Cercis reniformis `Oklahoma' have far superior foliage and make wonderful substitutes for the Eastern Redbud, particularly in non-irrigated areas. These are also better for central and western Oklahoma and Texas.

Cercis cultivars can be propagated by grafting onto seedlings, or by summer cuttings under mist or in a greenhouse.

Pests

Borers attack the trunk of older and stressed trees. Keep the plant vigorous.

Scale insects can usually be controlled with horticultural sprays.

Webworm can defoliate parts of the tree in summer and fall.

Diseases

Canker is the biggest problem with Eastern Redbud. Dieback begins as a canker on a branch. The cankers, at first small and sunken, enlarge to girdle the branch. Bark in the canker turns black and a crack forms between diseased and healthy bark. The fungus enters through wounds or dead and dying branches. Once girdled, the part of the stem beyond the canker wilts and dies. There is no chemical control. Prune out diseased branches.

Leaf spots can be a problem during wet weather. Since the disease is rarely serious, no chemical controls are suggested.

Verticillium wilt attacks and kills Eastern Redbud. Fertilize affected trees with nitrogen fertilizer and prune out wilted branches.