Second-Year Growth in Hybrid Poplars

Poplar Tree Growth

• A newly planted poplar tree needs at least one year to become fully established. The area in which it is planted must be free of weeds and the soil must be moist but well drained. While older well-established poplars tolerate wet soil, excessive moisture can cause the roots of younger trees to rot. First-year growth occurs primarily in the root zone and along the tree's central trunk. Hybrid poplar roots are shallow and grow to a distance that normally equals the spread of an adult tree. Beyond the first year, a hybrid poplar tree can grow from 5 to 8 feet per year. The Arbor Day Foundation lists it as a "fast-growing tree," which indicates a tree that can grow 2 feet or more in a year.

Getting Started

• While hybrid poplars can be grown from seeds, many property owners start with saplings purchased from nurseries or by mail. During the first year of growth, weed control is crucial, as young saplings do not compete well with other plants. It's important to keep the area at the base of the sapling free of all other growth, including grass. It's also important to water the tree regularly, as the tender sapling stage is when a hybrid poplar is least able to deal with hot dry weather. Regular deep watering is crucial to root growth and development. By the second year, the root system is usually sufficiently developed to seek out the water it needs, thus minimizing the need for additional water. As the tree's canopy continues to enlarge and provide more shade, weeds become less of a problem.

Propagation

• Hybrid poplar trees saplings are roughly 5 to 6 feet tall when ready for planting. Sold as bare-root plants, the main stems have several short lateral branches and unopened leaf buds. Grown under the right conditions, hybrid poplars can be cut down for use as firewood in as early as five years. Left untouched, they can grow as long as 50 years. Once fully established, cutting can be taken from adult trees and easily rooted in the soil. Also called "sticks," the whiplike branches root readily if given enough water, and trees that have been cut down often produce new growth within a very short time if their stumps are not removed. Poplars also sometimes reproduce by sprouting new seedlings at any point along their shallow roots.

Background

• Hybrid poplars are the product of cross-breeding using other members of the Populus tree family. The most common hybridization is done between Cottonwood (Populus deltoides) and black poplar (Populus nigra). Together, the genus is referred to as Populus x euramericana, but other species of poplars have been crossed with cottonwoods to produce hybrids. The trees were developed to fill a need for a quick source of firewood and for a species that produces fast results for use as windbreaks and in soil moisture control. Hybrid poplars are hardy in U. S. Department of Agriculture plant hardiness zones 3 to 8, and are more resistant to pests and disease than their parent species.