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Publication #ENH285

Cassia bicapsularis: Butterfly Bush1

Edward F. Gilman and Dennis G. Watson2

Introduction

While other trees are preparing for winter, butterfly bush is just waking up. This sprawling, semi-evergreen shrub, reaching a height of 8 to 10 feet with an equal spread, produces blossoms in fall that resemble golden butterflies. Bright yellow flowers appear at a time of year when little else is in bloom. This plant has a place in any sunny landscape.

Figure 1. 

Mature Cassia bicapsularis: Butterfly Bush


Credit:

Ed Gilman


[Click thumbnail to enlarge.]

General Information

Scientific name: Cassia bicapsularis
Pronunciation: KASS-ee-uh bye-kap-soo-LAIR-iss
Common name(s): Butterfly bush
Family: Leguminosae
USDA hardiness zones: 9A through 11 (Fig. 2)
Origin: not native to North America
Invasive potential: little invasive potential
Uses: specimen; container or planter; deck or patio; highway median
Availability: not native to North America

Figure 2. 

Range


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Description

Height: 8 to 12 feet
Spread: 8 to 10 feet
Crown uniformity: irregular
Crown shape: vase, round
Crown density: open
Growth rate: moderate
Texture: fine

Foliage

Leaf arrangement: alternate (Fig. 3)
Leaf type: even-pinnately compound
Leaf margin: entire
Leaf shape: obovate, ovate
Leaf venation: pinnate
Leaf type and persistence: semi-evergreen
Leaf blade length: less than 2 inches
Leaf color: green
Fall color: no color change
Fall characteristic: not showy

Figure 3. 

Foliage


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Flower

Flower color: yellow
Flower characteristics: very showy

Figure 4. 

Flower


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Fruit

Fruit shape: pod or pod-like
Fruit length: 1 to 3 inches, 3 to 6 inches
Fruit covering: dry or hard
Fruit color: brown
Fruit characteristics: does not attract wildlife; not showy; fruit/leaves not a litter problem

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, green
Current year twig thickness: medium
Wood specific gravity: unknown

Culture

Light requirement: full sun, partial sun, or partial shade
Soil tolerances: clay; sand; loam; slightly alkaline; acidic; well-drained
Drought tolerance: moderate
Aerosol salt tolerance: moderate

Other

Roots: not a problem
Winter interest: no
Outstanding tree: no
Ozone sensitivity: unknown
Verticillium wilt susceptibility: unknown
Pest resistance: resistant to pests/diseases

Use and Management

When knocked down by frost, the stems should be cut off at ground level and vigorous sprouts will emerge in spring. Butterfly bush benefits from frequent pinching of the young shoot tips during the growing season up to the beginning of September; this encourages branching and increases the number of flowers. Appropriate training can produce a very small specimen tree which looks nice growing in a low ground cover. Trees often fall over and will require staking to hold them upright. For this reason, it is easiest to place it in a shrub border among other shrubs that will help hold it erect. Well worth the effort to stake a specimen tree, if needed, since the tree is simply stunning in flower.

Tolerant of many soil conditions, butterfly bush needs full sun for best growth and flowering, and needs little care once established. Plant it and forget about it, except for occasional watering during drought. A good plant for highway median or roadside specimen or cluster planting.

Propagation is by seed or cuttings.

Pests

Foliage and flower buds are often eaten by caterpillars in the fall, but these can be easily picked off by hand. Cassia is otherwise seldom plagued by insect pests or diseases. Damaged or stressed cassia can be infested with trunk borers.

Diseases

No diseases are of major concern.

Footnotes

1.

This document is ENH285, one of a series of the Environmental Horticulture, UF/IFAS Extension. Original publication date November 1993. Reviewed February 2014. Visit the EDIS website at http://edis.ifas.ufl.edu.

2.

Edward F. Gilman, professor, Environmental Horticulture Department; Dennis G. Watson, former associate professor, Agricultural Engineering Department, UF/IFAS Extension, Gainesville, FL 32611.


The Institute of Food and Agricultural Sciences (IFAS) is an Equal Opportunity Institution authorized to provide research, educational information and other services only to individuals and institutions that function with non-discrimination with respect to race, creed, color, religion, age, disability, sex, sexual orientation, marital status, national origin, political opinions or affiliations. For more information on obtaining other UF/IFAS Extension publications, contact your county's UF/IFAS Extension office.

U.S. Department of Agriculture, UF/IFAS Extension Service, University of Florida, IFAS, Florida A & M University Cooperative Extension Program, and Boards of County Commissioners Cooperating. Nick T. Place, dean for UF/IFAS Extension.