Eastern redbud (Cercis canadensis)

Description

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Eastern redbud fact file

• Description
• Biology
• Range
• Habitat
• Status
• Threats
• Conservation
• Find out more
• Glossary
• References
• Print factsheet

Eastern redbud description

One of the first trees to bloom in early spring, the eastern redbud (Cercis canadensis) is an attractive species which produces one of North America’s most spectacular floral displays. Its showy profusion of small, pink to purplish flowers is borne in clusters over the entire tree, including the branches and trunk, and appears before the leaves have opened ^{(3) (4) (5) (6) (7)}.

A small, deciduous tree, the eastern redbud usually has a short trunk and a spreading or oval-shaped crown ^{(3) (4)}. Its thin bark is usually dark or reddish-brown and becomes scaly on older trees ^{(2) (3)}.

Unlike most other members of the pea family (Fabaceae), the eastern redbud is unusual in producing leaves that comprise single rather than multiple leaflets ^{(2) (4)}. The leaves grow at alternating points along the stems, and are heart- or kidney-shaped, with long, slender stalks, smooth margins, prominent veins and a tapering tip ^{(2) (3) (4) (5) (6) (8)}. The leaves of the eastern redbud become dark green with age, before turning bright yellow in the autumn ^{(3) (8)}. Each leaf measures around 7.5 to 12.5 centimetres in both length and width ⁽⁴⁾.

The flowers of the eastern redbud are borne on slender stalks, in clusters of four to eight ^{(3) (4)}. Each flower measures up to 1.2 centimetres in length ⁽⁴⁾ and has 5 rounded petals and 10 stamens ^{(3) (5) (8)}. The petals are arranged in a ‘butterfly’ shape, with a small upper petal enclosed by two lateral ‘wing’ petals, and two lower petals which are more or less fused to form a ‘keel’ ^{(3) (9)}. The fruit of the eastern redbud is a flat, leathery, thin-walled pod, which is oblong in shape and reddish-brown when mature ^{(2) (3) (5) (6) (8)}. The pod measures up to ten centimetres in length ^{(2) (4) (8)} and splits along two lines to release several hard, brown seeds ^{(2) (3) (6)}, which are oval and somewhat flattened ^{(2) (3)}.

Three varieties of the eastern redbud are recognised: Cercis canadensis var. canadensis (eastern redbud), Cercis canadensis var. mexicana (Mexican redbud) and Cercis canadensis var. texensis (Texas redbud) ^{(5) (7) (8) (10) (11)}. The eastern redbud is a popular ornamental tree and a number of commercially cultivated forms also exist, which vary in the colour and shape of their flowers and leaves ^{(6) (7)}.

Also known as

Canadian redbud, Judas tree, Mexican redbud, redbud, Texas redbud.

Synonyms

Cercis reniformis.

Size

Height: up to 12 m ⁽²⁾

Trunk diameter: up to 60 cm ⁽²⁾

Eastern redbud biology

The eastern redbud flowers in early spring, usually between March and May, with the flowers appearing before the leaves have opened ^{(3) (4) (5)} 6) ⁽⁷⁾. The showy flowers are bisexual, containing both male and female reproductive organs ^{(3) (4) (9)}, and are pollinated by bees ^{(3) (6) (8)}.

The seeds of the eastern redbud usually ripen from July to August, or sometimes later ⁽¹²⁾, and are often eaten by birds and squirrels ^{(3) (6) (8) (12)}. This colourful tree reaches maturity in about 75 years ⁽³⁾.

Unlike most members of the Fabaceae family, the eastern redbud is unusual in that it does not possess specialised root nodules containing nitrogen-fixing bacteria ⁽¹²⁾, which in other species take nitrogen from the air and convert it to nitrogen-containing compounds that benefit the plant ⁽⁹⁾. The bark of this species has been used by people for various medicinal purposes, and its flowers are sometimes eaten ^{(2) (5) (6) (8) (12)}.

Eastern redbud range

The eastern redbud is found in Ontario, Canada, and south throughout the eastern and south-central United States, as far as Mexico ^{(1) (7) (8) (11)}.

The variety Cercis canadensis var. canadensis occurs in Canada and the eastern U.S., while Cercis canadensis var.texensis occurs in the south-western U.S. and Cercis canadensis var.mexicana occurs in the south-western U.S. and into Mexico ^{(5) (7)}.

Eastern redbud habitat

Typically growing on rich, moist, sandy or loam soils (soils containing sand, clay and organic matter) ^{(3) (6)}, the eastern redbud is an understory species that can be found in open woods, ravines, along the borders of streams and in brushy areas ^{(3) (5) (6) (8)}. It is most common on well-drained sites on south-facing slopes, and does not tolerate flooding ^{(3) (6)}.

Eastern redbud status

The eastern redbud is classified as Least Concern (LC) on the IUCN Red List ⁽¹⁾.

Eastern redbud threats

There are not known to be any major threats to the eastern redbud, and it is not currently considered at risk of extinction ⁽¹⁾. This species is widely cultivated in the United States and other countries for its ornamental value ^{(3) (8)}.

However, some local populations of the eastern redbud may be under some degree of threat, with the species being listed as ‘Endangered’ in New Jersey and as ‘Special Concern’ in Connecticut ⁽¹¹⁾.

Eastern redbud conservation

Its listing as a threatened species in New Jersey and Connecticut may offer the eastern redbud a degree of legal protection in these states ⁽¹¹⁾. In Arizona, the eastern redbud is listed as ‘Salvage Restricted’ ⁽¹¹⁾, meaning that it can only be collected with a permit ⁽¹³⁾.

There are not known to be any other specific conservation measures currently in place for the eastern redbud.

Find out more

Find out more about the eastern redbud:

• USDA-NRCS Plant Guide - Eastern redbud:
  http://plants.usda.gov/plantguide/pdf/cs_ceca4.pdf

Find out more about plant conservation in the United States:

• Center for Plant Conservation:
  http://www.centerforplantconservation.org/

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Glossary

Deciduous

A plant that sheds its leaves at the end of the growing season.

Leaflets

The individual ‘leaf-like’ parts of a compound leaf.

Pollination

The transfer of pollen grains from the stamen (male part of a flower) to the stigma (female part of a flower) of a flowering plant. This usually leads to fertilisation, the development of seeds and, eventually, a new plant.

Stamen

The male reproductive organ of a flower. Each stamen is comprised of an anther (the pollen-producing organ) and a filament (stalk).

Variety

In taxonomy, the science of classifying organisms, variety is the rank below subspecies. Members of a variety differ from others of the same species in relatively minor ways.

References

1. IUCN Red List (September, 2011)
   http://www.iucnredlist.org/
2. Preston Jr, R.J. and Braham, R.R. (2002) North American Trees. Fifth Edition. Iowa State University Press, Ames, Iowa.
3. Leopold, D.J. (2003) Trees of New York State: Native and Naturalized. Syracuse University Press, Syracuse, New York.
4. Nelson, G. (2011) The Trees of Florida: A Reference and Field Guide. Second Edition. Pineapple Press, Sarasota, Florida.
5. Powell, A.M. (1998) Trees and Shrubs of the Trans-Pecos and Adjacent Areas. University of Texas Press, Austin, Texas.
6. Brakie, M. (2010) Plant Fact Sheet for Eastern Redbud (Cercis canadensis). USDA-Natural Resources Conservation Service, East Texas Plant Materials Center, Nacogdoches, Texas. Available at:
   http://plants.usda.gov/factsheet/pdf/fs_ceca4.pdf
7. Bajaj, Y.P.S. (Ed.) (1991) Biotechnology in Agriculture and Forestry 16. Trees III. Springer-Verlag, Berlin and Heidelberg.
8. USDA-NRCS Plant Guide - Eastern redbud, Cercis canadensis (September, 2011)
   http://plants.usda.gov/plantguide/pdf/cs_ceca4.pdf
9. Heywood, V.H. (1978) Flowering Plants of the World. Oxford University Press, Oxford.
10. Integrated Taxonomic Information System (ITIS) (September, 2011)
    http://www.itis.gov/
11. USDA PLANTS Database - Eastern redbud, Cercis canadensis (September, 2011)
    http://plants.usda.gov/java/profile?symbol=CECA4
12. Petrides, G.A. (1988) A Field Guide to Eastern Trees: Eastern United States and Canada, Including the Midwest. Houghton Mifflin Company, New York.
13. Arizona Game and Fish Department - Status Definitions (September, 2011)
    http://www.azgfd.gov/w_c/edits/hdms_status_definitions.shtml