Trochodendron aralioides
wheel tree
East Asia (Japan, South Korea, Taiwan)
Overview
Trochodendron aralioides is a broadleaf evergreen tree reaching 20–40 feet (6–12 m) in cultivation, occasionally taller in native forests. The leathery leaves measure 3–6 inches (8–15 cm) long, are elliptic with finely toothed margins, and cluster in whorl-like rosettes at the branch tips, leaving lengths of bare stem between. Bark is gray-brown and aromatic when cut, and the wood lacks vessel elements, a trait shared by few flowering plants. In late spring, branched clusters carry green flowers 0.4–0.6 inch (10–15 mm) across; each flower has no petals and a ring of 40–70 stamens radiating outward around a central whorl of green carpels, giving the bloom a wheel-like form. Growth is slow, often less than 12 inches (30 cm) per year once established. The species tolerates cool maritime climates and partial shade but is sensitive to prolonged drought and to hard freezes below its hardiness range. It develops a dense, pyramidal to rounded crown with age and holds its foliage through winter.
Native Range
Trochodendron aralioides is native to Japan, South Korea, and Taiwan, where it grows in temperate and subtropical mountain forests at elevations of 1,000–8,500 feet (300–2,600 m). It occurs as an understory and mid-canopy tree on moist, humus-rich slopes.Suggested Uses
Trochodendron aralioides is grown as an evergreen specimen tree, a screen, or a shade-tolerant component of woodland gardens. It suits cool maritime climates and shaded courtyards, spaced 10–15 feet (3–4.5 m) from structures and other trees. Container culture is possible while young but limited by the eventual size and slow recovery from root disturbance.How to Identify
Appearance
Size & Dimensions
Height20' - 40'
Width/Spread15' - 25'
Reaches mature size in approximately 30 years
Bloom Information
Flowering occurs in late spring, typically May to June, on terminal racemes holding 10–20 green flowers each. The petal-less blooms persist 2–3 weeks and mature into clusters of star-arranged follicles that ripen to brown by autumn. The green flowers blend with the foliage, and the radiating stamens are visible against the central green carpels.
Detailed Descriptions
Foliage Description
Glossy dark greenGrowing Conditions
Sun Requirements
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
Care & Maintenance
Care Guide
Trochodendron aralioides grows in moist, well-drained, humus-rich soil with a pH between 5.5 and 7.0. It tolerates partial shade to full sun in cool-summer regions and needs shelter from drying wind and afternoon heat in warmer zones. Soil kept consistently moist through the first three growing seasons supports establishment; mature trees withstand short dry spells but decline under extended drought. A 2–3 inch (5–8 cm) mulch layer conserves moisture and moderates root temperature. Growth averages under 12 inches (30 cm) per year, and feeding beyond one spring application of balanced fertilizer is seldom required. Foliage and young shoots are damaged by cold below USDA zone 7.Pruning
Trochodendron aralioides needs little pruning and develops its pyramidal to rounded crown without shaping. Dead or crossing branches can be removed in late winter before new growth begins. The slow growth rate makes corrective cuts infrequent, and heavy pruning produces sparse regrowth that can take several seasons to fill in.Pruning Schedule
J
F
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A
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winter