Eastern cottonwood (Populus deltoides) is a member of the poplar family of trees and occurs naturally near water in most parts of the United States. It's one of the fastest-growing deciduous trees in North America and can reach heights of more than 100 feet, offering bright yellow fall color and soft but durable timber for making furniture. Cottonwood needs moist sandy soil and plenty of sunshine to grow well, and needs very little pruning except when young, or when storm damage occurs.
Clean the blades of all pruning equipment before use. Dip them in boiling water for 30 seconds or wipe with a cloth dampened in rubbing alcohol. This prevents introduction of bacteria, fungus and insect eggs to pruning wounds.
Prune cottonwoods for shape and fast growth when they are young, in late winter or early spring when they are dormant. Dormant trees are less likely to suffer disease and shock when sap is not flowing and temperatures are cold.
Trim off branches from the lower third of young cottonwoods with long-handled pruning shears. Angle the blades at 45 degrees from the trunk and cut down and away, leaving 1/4-inch stub that will drain moisture and heal fast. Trimming lower branches focuses the tree's energy upward.
Cut crossing and rubbing branches from older cottonwoods with a pole-handled pruning saw that reaches up into the canopy. Rubbing branches causes bark injury, and cottonwood is soft enough as it is. Don't thin more than a third of the canopy foliage in any given year.
Prune dead or diseased wood at any time of year, as soon as you see it. Cottonwood is vulnerable to a number of diseases that can harm it if left untreated.
Cut branches more than 3 inches in diameter on mature cottonwoods with a pruning saw, using the three-cut method. Make the first cut a third of the way through the underside of the branch, 12 to 24 inches from the trunk. Make the second cut through the top of the branch, slightly beyond the first. The branch will snap of its own weight. Make the third cut at the trunk, leaving a short, angled stub.
Cut prunings and chip them for mulch or dispose of them in yard waste bags. Sterilize pruning equipment blades before storing or using them on other trees.
Things You Will Need
- Long handled pruning shears
- Pruning saw
- Pole-handle pruning saw
- Boiling water
- Cloth and rubbing alcohol (optional)
- Yard waste bags (optional)
- Wood chipper (optional)
- Expect your cottonwood to start producing seeds between the ages of 5 and 10. A mature cottonwood can produce as many as 48 million seeds per tree, each one with its own silky parachute.
- Don't cut cottonwood branches flush with the trunk. You're likely to tear delicate trunk bark and cause damage to the tree.