Trochodendron spp.

wheel tree

SunPart Shade – Full Sun

HardinessZones 7–9

Overview

Trochodendron spp. is a genus in the family Trochodendraceae represented by a single living species, the wheel tree (Trochodendron aralioides), native to the cool, moist forests of Japan, Korea, Taiwan, and southern China. It grows as an evergreen tree or large shrub 20-65 feet (6-20 m) tall, with smooth grey bark and leathery, oval to diamond-shaped leaves crowded in whorl-like clusters at the branch tips. The leaf margins are toothed toward the tip, and the foliage holds a glossy deep green year-round. In late spring it bears terminal racemes of small flowers that lack petals; each shows a ring of green stamens and carpels arranged like the spokes of a wheel, the source of the common name. The fruit is a ring of small follicles that splits to release winged seeds. The wood lacks the water-conducting vessels found in most flowering plants, moving water instead through tracheids. The genus needs cool, humid conditions and acidic, free-draining soil, and grows slowly.

Native Range

Native to East Asia, in the cool temperate and montane forests of Japan, Korea, Taiwan, and southern China.

Suggested Uses

Grown as a specimen and shade tree in cool-climate woodland gardens and large borders. Used where evergreen structure and wheel-shaped flowers are wanted in mild, moist regions.

How to Identify

Evergreen tree with leathery, diamond- to oval-shaped leaves clustered in whorl-like rosettes at the branch tips, their margins toothed toward the apex. Terminal racemes carry petalless green flowers whose stamens and carpels radiate like wheel spokes. Ring-shaped clusters of follicles follow.

Appearance

Size & Dimensions

Height20' - 65'

Width/Spread10' - 25'

Colors

Flower Colors

green

Foliage Colors

green

Fall Foliage Colors

no change

Bloom Information

Bloom Period

Spring Summer

Flowering occurs in late spring to early summer, roughly May to June. The petalless green flowers are held in upright racemes and draw small insects. Woody follicles develop through summer and release winged seeds in autumn.

Detailed Descriptions

Foliage Description

glossy deep green

Growing Conditions

Sun Requirements

SunPartial Shade SunFull Sun

Requires 3-8 hours of direct sunlight daily

• Full Sun: 6+ hours of direct sunlight

• Partial Shade: 3-6 hours of direct sunlight

• Full Shade: Less than 3 hours of direct sunlight

Soil Requirements

pH Range5.0 - 6.5(Acidic)

357912

Soil Types

loam peat sand

Drainagewell drained

Water & Climate

Water Needs

Medium

Frost Tolerance

hardy

Care & Maintenance

Care Guide

The wheel tree grows in part shade to full sun in cool, humid sites with acidic, free-draining soils kept evenly moist. It is intolerant of drought, heat, and exposed, windy positions, reflecting its montane forest origin. Growth is slow, and plants take many years to reach full size. Propagation is by seed or by semi-hardwood cuttings, both slow to establish. Few pests or diseases trouble it where soil and climate suit.

Pruning

Little pruning is needed beyond removing dead or damaged wood in late winter. The naturally layered, whorled form develops without shaping, and heavy cutting sets the plant back because regrowth is slow.

✓ Toxicity

Non-toxic

Tree