Populus balsamifera aka Cottonwood

Populus balsamifera, or balsam poplar, is a large deciduous tree. It belongs to the willow family, Salicaceae. Its native range spans northern North America and the northern Russian Far East. It grows near the northern tree line in North America. It also occurs farther south in some mountain areas. Its habitats include river bottoms, stream banks, and lake edges.

This fast-growing tree has an upright form and straight trunk. One growing reference gives 98 feet [30 metres] in height. It gives a spread of 26 feet [8 metres]. Oregon State lists heights of 80–130 feet [25–40 metres]. The bark has a reddish-gray tone and deep grooves. The alternate leaves have finely toothed edges and pointed or blunt tips. Their upper sides are dark green; their undersides are pale gray. Some leaves show orange-red resin marks beneath.

Sticky resin coats the buds and has a strong scent. Male and female flowers grow on separate trees. Wind carries pollen between them, so seed needs both sexes. The green flowers form hanging catkins in March and April. Female catkins are longer than male ones. Egg-shaped seed capsules release seeds with cotton-like hairs. Fresh seed stays viable for only a few days.

Give this tree full sun and room away from competing roots. It prefers deep, rich, moist soil that drains well. It accepts sand, loam, and clay, including heavy clay. It also tolerates soil flooding, though growth slows in wet ground. Poor acid soils and thin, dry soils also limit growth. Exposed upland sites do not suit it well. Chicago Botanic Garden lists USDA zones 2–9. Oregon State reports hardiness down to zone 1.

Balsam poplar can serve as a specimen or woodland canopy tree. It colonizes open ground, but later trees can shade it out. It tends to be short-lived, though some trees reach 150–200 years. Indigenous peoples used its bud resin to seal canoe seams. Records also describe resin use as an insect repellent. Traditional medicine used the buds for skin and lung complaints. PFAF lists the inner bark and bitter catkins as edible. Its hazard entry reports none known, but does not establish universal safety.