Redbud Cercis canadensis
INTRODUCTION
The
state tree of Oklahoma, Eastern
Redbud is a moderate to rapid-grower
when young, reaching a height
of 20 to 30 feet. Thirty-year-old
specimens are rare but they can
reach 35 feet in height forming
a rounded vase. Trees of this
size are often found on moist
sites. The splendid purple-pink
flowers appear all over the tree
in spring, just before the leaves
emerge. Eastern Redbud has an
irregular growth habit when young
but forms a graceful flattopped
vase-shape 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 extensively
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): Eastern Redbud
Family: Leguminosae
USDA hardiness zones: 4B through
9A
Origin: native to North America
Uses: container or above-ground planter;
large parking lot islands (> 200
square feet in size); wide tree lawns
(>6 feet wide); medium-sized parking
lot islands (100-200 square feet
in size); medium-sized tree lawns
(4-6 feet wide); recommended for
buffer strips around parking lots
or for median strip plantings in
the highway; near a deck or patio;
reclamation plant; shade tree; small
parking lot islands (< 100 square
feet in size); narrow tree lawns
(3-4 feet wide); specimen; sidewalk
cutout (tree pit); residential street
tree
Availability: generally available
in many areas within its hardiness
range
DESCRIPTION
Height: 20 to 30 feet
Spread: 15 to 25 feet
Crown uniformity: irregular outline
or silhouette
Crown shape: round; vase shape
Crown density: moderate
Growth rate: fast
Texture: coarse
Foliage
Leaf arrangement: alternate
Leaf type: simple
Leaf margin: entire
Leaf shape: orbiculate; ovate
Leaf venation: banchidodrome; pinnate;
palmate; reticulate
Leaf type and persistence: deciduous
Leaf blade length: 4 to 8 inches;
2 to 4 inches
Leaf color: green
Fall color: yellow
Fall characteristic: showy
Flower
Flower color: lavender; pink; purple
Flower characteristics: spring flowering;
very showy
Fruit
Fruit shape: pod
Fruit length: 1 to 3 inches
Fruit covering: dry or hard
Fruit color: brown
Fruit characteristics: does not attract
wildlife; no significant litter problem;
persistent on the tree; showy
Trunk
and Branches
Trunk/bark/branches: bark is thin
and easily damaged from mechanical
impact; droop as the tree grows,
and will require pruning for vehicular
or pedestrian clearance beneath the
canopy; routinely grown with, or
trainable to be grown with, multiple
trunks; not particularly showy; tree
wants to grow with several trunks
but can be trained to grow with a
single trunk; no thorns strong structure
Breakage: susceptible to breakage
either at the crotch due to poor
collar formation, or the wood itself
is weak and tends to break
Current year twig color: brown
Current year twig thickness: medium
Culture
Light requirement: tree grows in
part shade/part sun; tree grows
in full sun
Soil tolerances: clay; loam; sand;
acidic; occasionally wet; alkaline;
well-drained
Drought tolerance: high
Aerosol salt tolerance: none
Soil salt tolerance: poor
Other
Roots: surface roots are usually
not a problem
Winter interest: no special winter
interest
Outstanding tree: not particularly
outstanding
Invasive potential: little, if any,
potential at this time
Ozone sensitivity: sensitive or moderately
tolerant
Verticillium wilt susceptibility:
susceptible
Pest resistance: long-term health
usually not affected by pests
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 Eastern
Redbud 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
cultivars of Eastern Redbud may be
seen: forma alba - white flowers,
blooms about a week later;‘Pink
Charm’ - flowers pink; ‘Pinkbud’ -
flowers pink;‘Purple Leaf’ -
young foliage purple; ‘Silver
Cloud’ - leaves variegated
with white; ‘Flame’ -
more erect branching, flowers double,
blooms later, sterile so no seed
pods form. ‘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 Eastern Redbud, particularly
in non-irrigated areas. These are
also better for central and western
Oklahoma and Texas, as is the Mexican
Redbud. Cercis are best propagated
by seed. Use ripe seed to plant directly,
or, if seed has been stored, stratification
is necessary before sowing in a greenhouse.
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.
by Edward F. Gilman and Dennis G. Watson
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