Populus fremontii aka Cottonwood

Populus fremontii belongs to the willow family and sheds its leaves. People call it Fremont's cottonwood or western cottonwood. It grows in the western United States and Mexico. Its range spans California, Arizona, New Mexico, Nevada, and Utah. It also grows in western Texas. It lives by streams and at desert waterholes. These wet sites give this large tree the water it needs.

In gardens, it grows about 40–60 feet (12–18 metres) tall. Some trees reach 100 feet (30 metres). One more source gives 82 feet (25 metres). It grows fast but has a short life. Its crown may be broad and round, cylindrical, or flat-topped. Young trunks and branches have smooth bark. With age, bark turns gray-brown, with deep grooves and flat ridges. Thick twigs bear large, pointed buds with no sticky resin.

Leaves grow in an alternate pattern, taking turns along the stems. Their shapes range from broad hearts to near triangles. They have coarse teeth at the edges and flat stalks. Their tops shine green or yellow-green. Some have fine hairs beneath. Fall leaves may turn lemon-yellow. In mild climates, leaves can last well into winter. Male and female flowers grow on separate trees. Yellow-green catkins hang down in early spring, before leaves grow. The tree blooms in March and April. Wind moves pollen from tree to tree. Small, pale-brown seed cases, called capsules, split open. They then shed many cottony seeds.

Give this tree sun and space for its roots. It likes moist ground and copes with floods and silt deposits. It grows best in deep, rich soil that drains well. It accepts sand, loam, clay, and even strongly alkaline soil. Poor acidic soil and thin, dry ground slow its growth. Exposed upland sites do not suit it. Sources differ on how much cold it can bear. Oregon State gives USDA zone 5. Plants For A Future lists zones 2–9 but notes tender forms. Its large crown can form a woodland garden canopy. Roots near the surface may spread with force. The cottony seeds can make litter.

Plants For A Future lists catkins and inner bark as edible. People have also chewed young green seedpods as gum. The source lists no known hazards; this does not confirm safety. It notes past use of bark to prevent scurvy. Its records also list bark and leaf washes for medicinal use. People have split young twigs to make baskets. The soft, weak wood has served as local fence posts and fuel.