White Poplar (Populus alba)

Family: Salicaceae or Willow

Leaves: Alternate; simple; often resembles a maple leaf in shape with very coarse teeth or lobes on margin; base rounded; 1" to 4" long; deciduous; dark green and glabrous above; white and woolly beneath; petioles hairy, 1/2" to 1-1/2" long, not flattened laterally.

Twigs/buds: Twigs slender; green-gray; covered with fine white hairs. Terminal bud more or less woolly.

Flowers/fruit: Dioecious. Fruit an oval capsule, 1/4" long, several together on a slender stalk like a string of beads; seeds tufted, small, light brown.

Bark: Green-white to bright white; with dark cracks and ridges when older; very characteristic.

Wood: Heartwood reddish-yellow; sapwood almost white; soft, light, fairly weak or brittle, and prone to breakage (e.g., during storms); used to make match sticks and for pulpwood.

General: Native to Europe. Often wrongly called silver maple. A large tree, grows rapidly in favorable locations, also thrives under less favorable conditions. Many root suckers (sprouts) occur around the tree.

Landscape Use: Planted in the past around farms and ranches and still sometimes seen in those locations, even if abandoned. Beautiful large tree, but root suckers are aggressive and wood is weak, similar to aspen. Some cultivars are available, but plant only in large, open areas where a troublesome tree will be less trouble. Golden fall color is occasionally nice. Zones 3-9.

Comments and Limitations:
- Weak wood and/or branch structure.
- Sucker (sprout) growth can be a problem.
- Prefers abundant water.

Black Cottonwood (Populus trichocarpa)

Family: Salicaceae or Willow (Poplar)

Leaves: Ovate to ovate-lanceolate; rounded base and angled; 3" to 6" long, 3" to 4" wide; acute to acuminate apex; rounded base; finely serrate margin; dark green above, paler beneath; petiole round, slender, long.

General: Some sources show this as native to extreme northern Utah; at any rate uncommon.

Landscape Use: Not planted and no cultivars available. Zones 3-8.

Comments and Limitations:
- Weak wood and/or branch structure.
- Prefers abundant water.

Fremont Cottonwood (Populus fremontii)

Family: Salicaceae or Willow (Poplar)

Leaves: Deltoid to kidney-shaped; 3" to 6" long, 4" to 5" wide; deciduous; rounded teeth on margin; pointed, short apex; glabrous; turn bright gold in fall; petiole 1-1/2" to 3" long, flattened laterally, causing leaf to flutter in the wind.

Twigs/buds: Twigs yellow-brown and angular. Terminal buds 3/4" long, pointed, shiny-brown, resinous, fragrant when crushed.

Bark: Light green, smooth on young trunks; on older trunks thick, gray, deeply furrowed with flat-topped ridges.

Wood: Fairly unimportant. See eastern cottonwood for description.

General: Native from about the Wasatch Front south including lower-elevation river drainages (Green and Colorado) in southern Utah and throughout the Southwest. Usually found naturally along streams.

Landscape Use: Rarely used and cultivars are not available, but it is a good, large cottonwood that would be worth having in the right setting. Zones 5-9.

Comments and Limitations:
- Weak wood and/or branch structure.
- Prefers abundant water.

Narrowleaf Cottonwood (Populus angustifolia)

Family: Salicaceae or Willow (Poplar)

Leaves: Lanceolate to ovate-lanceolate; 2" to 4" long, 1/2" to 1-1/2" wide; narrowest leaf of the cottonwoods found in Utah; long, tapered apex; deciduous; finely to coarsely serrate; petiole short (less than 1/3 length of blade) and not flattened laterally.

Twigs/buds: Twigs slender; round; glabrous; yellow-green when young and light gray when older. Terminal bud 1/4" to 3/4" long, sharp-pointed, resinous and aromatic, covered by brown overlapping scales.

Flowers/fruit: Fruit an oval capsule, 1/4" long, several together on a slender stalk like a string of beads; seeds tufted, small, light brown.

Bark: Smooth and light yellow-green when young, becoming shallowly furrowed on older trunks.

Wood: Unimportant and seldom used. See eastern cottonwood for description.

General: Native in from western Great Plains through the Intermountain West from Mexico to Canada, including most of Utah. Grows along streams at moderate to low elevations; prefers moist soils and is shade intolerant. Utah's most common native cottonwood. Crowns tend to be somewhat narrow. Easily identified by its narrow leaves, but can hybridize with some cottonwoods. One common hybrid is lanceleaf cottonwood (Populus x acuminata), a cross between P. angustifolia and either P. deltoides, P. fremontii, or P. balsamifera.

Landscape Use: Rarely used and no cultivars are available. Would be alright where a cottonwood is appropriate (needs plenty of water). Cottonwoods and willows can easily be propagated by taking 10" or longer cuttings off of young branches in the winter and planting them in the spring with about an inch showing above ground. The resulting tree is genetically identical to the original. Zones 3-9.

Comments and Limitations:
- Weak wood and/or branch structure.
- Prefers abundant water.

Quaking Aspen (Populus tremuloides)

Family: Salicaceae or Willow (Poplar)

Leaves: Simple; alternate; round to broadly ovate; 1-1/2" to 3" diameter; deciduous; finely serrate margin; acute apex; glabrous; yellow-green to green, turning bright yellow to orange in fall; petiole 1-1/2" to 3" long, flattened laterally, causing leaf to flutter in the wind.

Twigs/buds: Twigs slender; glabrous; red-brown. Terminal bud 1/4" to 1/2" long, sharp-pointed, sometimes resinous, covered by red-brown overlapping scales; lateral buds smaller, curve inward.

Flowers/fruit: Fruit a capsule; narrow conical; 1/4" long; gray and hairy; seeds small, tufted, light brown.

Bark: Smooth; green-white to cream colored; becomes furrowed on older trunks.

Wood: Gray-white to light gray-brown; sapwood lighter and merges gradually into heartwood; straight grained; fine textured; growth rings unclear; diffuse-porous; used for lumber, pallets, crates, pulp, and matches.

General: Native in most of the northern and western U.S. and Canada, including higher elevations in Utah. Generally forms single aged stands through root sprouts after a fire or other disturbance; grows in clumps or "clones" that are genetically identical since stems are all attached to the same root system. Relatively short-lived. Grows in cool, moist areas. Very shade intolerant.

Landscape Use: Over-planted in Utah; also found where homes are built into native aspen areas. Native trees do well, but aspen does not like the heat and dry conditions in our lower valleys. Stressed aspens suffer from leaf scorch, leaf spot, borers, cankers, galls, occasionally iron chlorosis, and many other problems. Best grown in cooler high-mountain climates that it is used to. If grown at low elevations, avoid problems with older, larger trees by managing selected aspen sprouts in a large, mulched bed; remove stems before they get very large. Zones 3-7.

Comments and Limitations:
- May be insect and/or disease prone, especially when stressed.
- Sucker (sprout) growth can be a problem.
- Rarely should be planted, though limited use in specific situations may be justified.