Tree-of-heaven
Also known as
Ailanthus, Stink tree, Varnish tree, Heaven tree, Chinese sumac, Ghetto palm
Keep this plant’s care guide close at hand.
Get the appAbout Tree-of-heaven
Ailanthus altissima, commonly called tree-of-heaven, is a fast-growing, deciduous tree native to China and widely naturalized across temperate regions worldwide. It typically reaches 15–25 m (50–80 ft), with smooth gray bark and large, pinnate leaves up to 1 m long bearing 10–41 leaflets with characteristic glandular notches near the base. Leaves and stems emit a strong, acrid odor when crushed. It is dioecious: male trees produce malodorous yellow-green flowers, while female trees bear showy clusters of papery samaras that ripen to reddish-tan. Exceptionally tolerant of drought, pollution, compacted and alkaline soils, it readily colonizes disturbed sites and forms dense thickets through prolific seed set and root suckering. Wood is relatively weak and the species can be short-lived, but it may grow over 1 m per year when young. Allelopathic compounds (notably ailanthone) suppress neighboring vegetation. In many regions, it is considered invasive; verify local regulations and avoid intentional planting where restricted.
Taxonomy
Properties & Requirements
How to care for Tree-of-heaven
Water
Once established in the ground, tree-of-heaven is highly drought tolerant and rarely needs supplemental irrigation except during prolonged heatwaves. For the first 1–2 growing seasons, water deeply and infrequently to encourage deep roots—allow the top 5–8 cm (2–3 in) of soil to dry between soakings. In containers, water when the top 2–3 cm (1 in) is dry, applying enough to drain freely; never allow pots to sit in water. Avoid chronic waterlogging, which promotes weak roots and stem dieback.
Light
Full sun (6+ hours of direct light) yields the best vigor, denser branching, and reduced leaning. Ailanthus will tolerate partial shade and seedlings often establish under light canopy cover, but growth slows and form becomes leggier with less light. In urban settings, southern or western exposures are ideal. Container-grown plants should be acclimated gradually to intense sun to prevent leaf scorch, especially following indoor overwintering or extended cloudy periods.
Nutrients
This species thrives in nutrient-poor, compacted, or alkaline soils and typically requires no fertilizer when planted in-ground. For container-grown specimens, use a balanced, slow-release fertilizer (e.g., 10-10-10 or 14-14-14) at half rate in early spring, avoiding excess nitrogen that can promote weak, lanky growth. Maintain a slightly gritty, well-drained substrate and refresh the top layer annually with composted bark or leaf mold. Flush containers periodically to prevent salt buildup, and discontinue feeding by late summer.
Temperature
Extremely hardy and heat tolerant, Ailanthus grows well in USDA zones roughly 4–9. Established trees can withstand winter lows near −25 °C (−13 °F) and summer highs exceeding 38 °C (100 °F). Young seedlings may suffer in late spring frosts; protect first-year plants if hard freezes threaten. Favor sites with good air circulation to limit fungal issues in humid climates. Container plants are best overwintered in a cold, sheltered location where roots are protected from repeated freeze–thaw cycles.
