Kalopanax pictus: Castor-Aralia1

Edward F. Gilman and Dennis G. Watson 2

Introduction

With massive, spreading branches and large, 7- to 12-inch-diameter, dark green, multi-lobed leaves, Castor-Aralia provides dense shade below its canopy and makes an ideal shade tree. Growing 40 to 50 feet high with an equal spread, Castor-Aralia is deciduous, the leaves turning a faint red in fall before dropping. While the young stems are armed with short, yellow prickles, the mature trunk is attractively ridged and blackened. The 1-inch-diameter, white flowers appear in dense, 12- to 24-inch-long terminal panicles and attract quite a few bees. This is not a problem on larger specimens since flowers are borne up in the tree away from the ground. The small black fruit which ripens in early fall is eagerly consumed by birds.

Figure 1. Mature Kalopanax pictus: Castor-Aralia
Figure 1.  Mature Kalopanax pictus: Castor-Aralia

General Information

Scientific name: Kalopanax pictus
Pronunciation: kal-oh-PAN-acks PICK-tus
Common name(s): Castor-Aralia, prickly castor-oil tree
Family: Araliaceae
USDA hardiness zones: 5A through 7B (Fig. 2)
Origin: not native to North America
Invasive potential: invasive non-native
Uses: tree lawn > 6 ft wide; specimen; shade
Availability: not native to North America

Figure 2. Range
Figure 2.  Range

Description

Height: 40 to 50 feet
Spread: 40 to 60 feet
Crown uniformity: irregular
Crown shape: round
Crown density: dense
Growth rate: moderate
Texture: coarse

Foliage

Leaf arrangement: alternate (Fig. 3)
Leaf type: simple
Leaf margin: lobed
Leaf shape: star-shaped
Leaf venation: palmate
Leaf type and persistence: deciduous
Leaf blade length: 8 to 12 inches
Leaf color: green
Fall color: yellow, red
Fall characteristic: not showy

Figure 3. Foliage
Figure 3.  Foliage

Flower

Flower color: white/cream/gray
Flower characteristics: showy

Fruit

Fruit shape: round
Fruit length: less than .5 inch
Fruit covering: fleshy
Fruit color: black
Fruit characteristics: attracts squirrels/mammals; not showy; fruit/leaves not a litter problem

Trunk and Branches

Trunk/bark/branches: branches don't droop; showy; typically one trunk; no thorns
Pruning requirement: needed for strong structure
Breakage: resistant
Current year twig color: brown
Current year twig thickness: very thick
Wood specific gravity: unknown

Culture

Light requirement: full sun
Soil tolerances: clay; sand; loam; alkaline; acidic; well-drained
Drought tolerance: high
Aerosol salt tolerance: unknown

Other

Roots: not a problem
Winter interest: yes
Outstanding tree: yes
Ozone sensitivity: unknown
Verticillium wilt susceptibility: unknown
Pest resistance: free of serious pests and diseases

Use and Management

This tree could be planted more often in landscapes, but seeds germinate readily in the landscape. Use it with caution near open fields and wetlands. The large size and coarse texture probably make it best suited for large-scale landscapes, such as golf courses, parks, business complexes and campuses, but it could be tried along streets where there is plenty of soil space for root expansion.

Castor-Aralia should be grown in full sun on well-drained soil and will tolerate alkaline soil. While drought-tolerant once established, Castor-Aralia should receive ample moisture until then. Any pruning should be done in late spring, and Castor-Aralia is considered a long-lived tree.

Propagation is by seed.

Pests and Diseases

No pests or diseases are of major concern.

Footnotes

1. This document is ENH-494, one of a series of the Environmental Horticulture Department, UF/IFAS Extension. Original publication date November 1993. Revised December 2006. Reviewed March 2014. Visit the EDIS website at https://edis.ifas.ufl.edu.
2. Edward F. Gilman, professor, Environmental Horticulture Department; and Dennis G. Watson, former associate professor, Agricultural Engineering Department, UF/IFAS Extension, Gainesville, FL 32611.

Publication #ENH-494

Date: 2014-09-30
Southern Trees Fact Sheets

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Contacts

  • Michael Andreu