Populus trichocarpa
Common name: 
Black Poplar
Black Cottonwood
Pronunciation: 
pop-U-lus tri-ko-KAR-pa
Family: 
Salicaceae
Genus: 
Populus
Synonyms: 
Populus balsamifera subsp. trichocarpa
Type: 
Broadleaf
Native to (or naturalized in) Oregon: 
Yes
  • Deciduous tree, to 40 ft (12 m) in 15 years, finally to 150 ft (45 m), trunk long and straight, narrow crown.  Bark dark gray-brown with age, in flat-topped ridges alongside V-shaped grooves.  Winter buds round or slightly angled, about 2 cm long with 6-7 scales, long pointed, orange-brown, very resinous and fragrant (balsam odor); apparently the fragrance is especially pronounced in the spring as the leaves unfold.  Leaves alternate, simple, broadly ovate, 7-12 cm long, base usually rounded (sometimes wedge- or heart-shaped), finely toothed, dark green above, silvery green below, often with brown resin blotches, petiole round, not flattened.  Flowers in long catkins, male (pollen) catkins 4-5 cm; female (seed) catkins 6-8 cm long, extending to 12-15 cm prior to seed release.  The seed catkins bear nearly spherical capsules, about 4 mm, which split into 3 parts to release silky tufts ("cotton") with attached small seeds (about 2 mm long).  Terminal buds 17-20 mm long with 6-7 visible scales, lateral buds parallel to twig.
  • Sun, prefers moist situations, but tolerates poor and dry soils.  Wood very brittle.  Female trees release a substantial amount of "cotton", which some consider a nuisance.
  • Hardy to USDA Zone 4     Native range from southern Alaska to southern California, east to the Rocky Mountains.  Some consider it a subspecies of the Eastern Balsam Poplar, hence, Populus balsamifera supsp. tricocarpa.
  • trichocarpa: hairy fruited; from the Greek thrix, a hair, and karpos, fruit.
  • Corvallis: many at the confluence of Marys River and the Willamette River.
Click image to enlarge
  • emerging male (pollen) catkins, spring

    emerging male (pollen) catkins, spring

  • male (pollen) catkins

    male (pollen) catkins

  • expanding male (pollen) catkins

    expanding male (pollen) catkins

  • expanding leaves

    expanding leaves

  • leaves and female (seed) catkins

    leaves and female (seed) catkins

  • seed (fruit) catkins, late spring

    seed (fruit) catkins, late spring

  • seed release, late spring

    seed release, late spring

  • seeds

    seeds

  • plant habit

    plant habit

  • plant habit, large tree

    plant habit, large tree

  • leaves

    leaves

  • leaves and buds

    leaves and buds

  • leaves, comparison

    leaves, comparison

  • leaf margins, comparison

    leaf margins, comparison

  • plant habit, fall

    plant habit, fall

  • leaves, fall

    leaves, fall

  • plant habit, winter

    plant habit, winter

  • trunk, bark

    trunk, bark

  • winter twigs and buds, comparison

    winter twigs and buds, comparison