Fremont cottonwood

Botanical name

Populus fremontii

Type

Native deciduous hardwood

Height

About 20 to 112 feet

Trunk

From about 20 inches to more than 12 feet across

Lifespan

More than 130 years

Where it grows here

Valley floors and waterways. In Nevada it is recorded from about 2,160 to 5,460 feet.

It is a native of streams and ditches across the Southwest. In town it grows wherever its roots find steady water: along old irrigation ditches, river bottoms and well-watered lawns.

How to identify it

• A broad, rounded crown on a heavy trunk
• Bark that is smooth on young trees and deeply furrowed on old ones
• Triangular leaves that flutter and turn yellow in fall
• Cottony seed released by female trees in late spring

Why big cottonwoods become a problem

The US Forest Service describes Fremont cottonwood as fast-growing, with wood that is relatively soft and weak and that has low resistance to decay. A tree that adds size quickly on weak wood builds long, heavy limbs.

It is also tied to water. The Forest Service notes the species is vulnerable to drought until its roots reach the water table. When a ditch is piped or the lawn irrigation stops, a mature cottonwood declines and starts shedding dead wood.

Pruning

Dead and hazardous branches can come off at any time. For other pruning, late winter, while the tree is dormant, is the time for most deciduous trees. Good pruning on a cottonwood removes dead wood and reduces the weight of long limbs. Topping it is not pruning and leaves weak regrowth.

When removal is the usual answer

• Decay in the trunk or at the base
• Large dead sections in the crown
• A heavy lean or cracked unions over a house
• Roots damaging pipes, a septic tank or a foundation

Big cottonwoods in tight yards are a job for crane-assisted removal. The species sprouts from stumps and roots, so ask for stump grinding if you do not want it back.