Ailanthus altissima aka Tree Of Heaven

Ailanthus altissima is known as tree of heaven. This deciduous tree belongs to the Simaroubaceae family. Its native range covers China and Taiwan. It now grows wild across much of the United States. It grows along roads, fences, clearings, and woodland edges. It also takes root in cracks in city paving. Its fast growth and spread make it invasive.

In gardens, trees reach 40–60 feet [12–18.3 metres] tall. Their spread ranges from 15–60 feet [4.6–18.3 metres], depending on the source. Some trees reach 80 feet [24.4 metres] in height. The crown spreads outward, with few thick, open branches. Root suckers can form dense stands around the tree. The bark starts smooth and pale gray. Young twigs have fine hairs and a reddish-brown tint. The soft wood breaks with ease during storms.

The green leaves grow in an alternate pattern. Each pinnate leaf measures 1.5–2 feet [0.46–0.61 metres] long. It holds many leaflets with mostly smooth edges. Teeth and glands sit near each leaflet's base. Crushed leaves and broken twigs give off an unpleasant smell. Fall leaves add little color. Yellow-green flowers grow in panicles in May and June. Male and female flowers occur mostly on separate trees. Male flowers have a strong, unpleasant smell. Female trees bear samaras with flat, twisted wings. These fruits turn from yellow or red to brown. Clusters can stay on the tree through winter. Wind and water carry the seeds away.

The tree grows in sun or partial shade. It accepts clay, loam, sand, and rocky ground. Acid, neutral, and alkaline soils all suit it. It tolerates drought, heat, salt, poor soil, and city pollution. Well-drained ground suits it, from dry to moist conditions. Sources place it in USDA zones 4–8 and UK rating H6. Its large leaves and tough nature once favored street planting. Leaves provide dye, while leaves and wood supply paper fibre. Its spread makes it a poor choice for gardens. UK rules ban its sale and require control of existing plants.

Seeds and root suckers help it crowd out native plants. Roots can damage drains and building foundations. Trees tend to have short lives and shed messy fruit. Verticillium wilt can affect them; spotted lanternflies use them as hosts. Cooked leaves have served as food during shortages. This is not evidence of safe routine use. Leaves are toxic to domestic animals, and contact can cause rashes. Pollen can trigger hay fever. Traditional medicine uses the bark, but its safety needs caution.