Introduction

This rounded, deciduous tree eventually has wide-spreading branches, which are green when young and covered with spines, often becoming grey and sometimes losing their coarse, sharp spines. Young trees can have a columnar or upright form. The spiny trunk is unusually thick and remains green even on older trees. Floss silk tree can reach 50 feet in height with an equal or greater spread, and grows rapidly the first few years, then more slowly. Some trees maintain a relatively narrow crown with one straight trunk while others are wide-spreading, particularly on older specimens. The large, showy, pink and white, five-petaled flowers, which somewhat resemble narrow-petaled hibiscus, are produced in small clusters in fall and winter (usually October) when the tree is nearly bare. The fruits are large, 8-inch-long, pear-shaped, woody capsules, filled with silky, white, kapok-like floss and pea-like seeds. Floss from the seeds was used for stuffing pillows, and thin strips of the bark have been used to make rope.

General Information

Scientific name: Chorisia speciosa

Pronunciation: koe-RIZZ-ee-uh spee-see-OH-suh

Common name(s): Floss silk tree

Family: Bombacaceae

USDA hardiness zones: 9B through 11 (Fig. 2)

Origin: not native to North America

Invasive potential: has been evaluated using the UF/IFAS Assessment of the Status of Non-Native Plants in Florida's Natural Areas (Fox et al. 2005). This species is not documented in any undisturbed natural areas in Florida. Thus, it is not considered a problem species and may be used in Florida.

Uses: shade; specimen; street without sidewalk; highway median

Availability: not native to North America

Description

Height: 35 to 50 feet

Spread: 40 to 55 feet

Crown uniformity: irregular

Crown shape: upright/erect, round, pyramidal

Crown density: moderate

Growth rate: fast

Texture: coarse

Foliage

Leaf arrangement: alternate (Fig. 3)

Leaf type: palmately compound

Leaf margin: serrate

Leaf shape: elliptic (oval)

Leaf venation: pinnate

Leaf type and persistence: deciduous

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

Leaf color: green

Fall color: no color change

Fall characteristic: not showy

Flower

Flower color: pink, white/cream/gray

Flower characteristics: very showy

Fruit

Fruit shape: oval, round

Fruit length: 6 to 12 inches

Fruit covering: dry or hard

Fruit color: brown, white/gray

Fruit characteristics: does not attract wildlife; showy; fruit/leaves not a litter problem

Trunk and Branches

Trunk/bark/branches: branches don't droop; very showy; typically one trunk; no thorns

Pruning requirement: needed for strong structure

Breakage: resistant

Current year twig color: green

Current year twig thickness: medium

Wood specific gravity: unknown

Culture

Light requirement: full sun

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

Drought tolerance: high

Aerosol salt tolerance: low

Other

Roots: can form large surface roots

Winter interest: yes

Outstanding tree: yes

Ozone sensitivity: unknown

Verticillium wilt susceptibility: unknown

Pest resistance: free of serious pests and diseases

Use and Management

An excellent specimen tree for parks, parking lots, and other large landscapes, floss silk tree is spectacular when in bloom, producing an outstanding show of color in the fall. Large roots often form at the base of the trunk just beneath the soil, so be careful not to plant the tree too close to sidewalks or pavement. Fifteen feet from curbs, driveways, and sidewalks should be adequate.

Prune the tree to be sure that only one central trunk develops when the tree is young. The central leader becomes less vigorous in middle age, allowing lateral limbs to develop into the main structure of the tree and produce a spreading form. Although most branches are horizontal and well attached to the tree, upright branches can develop with embedded bark that can cause a branch to split from the trunk. Prevent this by pruning the major limbs so they remain less than half the diameter of the trunk.

Flowering best in full sun, floss silk tree will thrive on any reasonably fertile soil with good drainage. It is not salt tolerant but does tolerate high pH. Grafted trees are preferred as they bloom earlier and at a smaller size.

Two grafted selections are available: 'Majestic Beauty' has rich pink flowers, and 'Los Angeles Beautiful' has wine red flowers. The cultivar 'Monsa' has a thornless trunk and pink fall flowers.

Propagation is by seed or grafting.

Pests and Diseases

No pests or diseases are of major concern.

Literature Cited

University of Florida, Institute of Food and Agricultural Sciences. 2018. "Assessment of Non-native Plants in Florida's Natural Areas" (https://assessment.ifas.ufl.edu, 4/29/2019) Gainesville, FL, 32611-4000, USA.