Populus grandidentata aka Canadian Aspen

Populus grandidentata, or bigtooth aspen, belongs to the willow family. This deciduous tree grows in temperate parts of North America. Its native range spans parts of Canada and the eastern United States. Records extend south to North Carolina and Tennessee. Other names include large-toothed aspen, paper poplar, and Canadian aspen.

Garden trees reach 50–70 feet [15.2–21.3 metres] tall. Their crowns spread 20–40 feet [6.1–12.2 metres] wide. Young trees have a pointed, pyramidal shape. Older crowns become open, uneven, and more oval. The tree grows fast but has a short life. Stout young stems have a reddish-brown colour. Bark starts thin and grey with a green tint. Old trunks develop cracks and dark brown bark with red tones.

The simple leaves grow one after another along each stem. They have dark green tops and grey hairs beneath. Broad blades carry large teeth along their upper edges. The lower edges lack teeth, and the tips are pointed. Leaves turn yellow before they fall in autumn. Pointed buds have overlapping scales with hairy edges. Hanging catkins open before the leaves, from March to April. Male and female flowers grow on separate trees. Wind carries pollen between them; one tree cannot fertilise itself. Sources differ on flower colour, reporting yellow, white, or sex-linked shades. Green, downy fruit capsules release seeds with cotton-like hairs. Seeds ripen in April, according to Plants For A Future.

Give this tree full sun and fertile, moist soil. Oregon State also lists part shade as suitable. Other sources stress its poor tolerance of shade. It grows in sand, loam, or clay with good drainage. It accepts mildly acid through mildly alkaline soil. UConn reports a preference for wet ground and easy transplanting. Chicago lists USDA zones 3–5; Oregon State notes possible zone 2 hardiness. The tree provides shade in lawns and large street spaces. It attracts butterflies and can help start new woodland. Other trees can later shade it out. Its soft wood serves mainly as pulp for paper.

Root suckers and canker can cause problems. Keep it away from drains, sewers, septic tanks, and paving. The inner bark has a recorded food use after boiling. Plants For A Future gives it a low food rating. That source reports no known hazards, rather than proven safety.