Taxonomy, Botanical Classification, Traits of Lombardy Poplar Trees
Plant taxonomy classifies Lombardy poplar trees as a cultivar of Populus nigra. The most common cultivar is "Italica." Like quaking aspens (P. tremuloides), they are in the willow family and are broadleaf, deciduous trees.
Lombardy poplar trees are best known for their columnar form and unusual branching structure. Their branches start close to the ground and parallel to the trunk. At maturity, they will reach 40 to 50 feet in height, with a spread of just 10 to 15 feet. Their fall foliage is a yellow color, but they are not primarily grown for their autumn display value.
Growing and Care Tips
Lombardy poplar trees are grown in planting zones 3 to 9. Grow them in well-drained soils in full sun.
These trees are susceptible to borers, cytospora canker, and bacterial wet wood, reducing their lifespan. But long before they die, they may be disfigured by these pests and diseases, rendering them unattractive as landscape plants and necessitating their removal. A similar tree, the upright European aspen (Populus tremula "Erecta"), is said to be more disease-resistant.
When it is time to remove Lombardy poplars, be thorough in removing as much of the root system as possible. Lombardy poplars send out suckers throughout their lives, even from their stumps after they have been cut down. Some hire pros with stump grinders to help get rid of them but if you have planted a long row of Lombardy poplars, this can run into quite a bit of money (and it still does not remove the root system). Another consideration is that the roots of Lombardy poplars are invasive and damage drainage systems if planted too close by them.
Uses for Lombardy Poplar Trees in Landscaping
Lombardy poplars are fast-growing trees, growing as much as 6 feet per year. This makes them a popular choice when people want "living wall" privacy screens or windbreaks in a hurry. To serve this function, they are planted in a row and spaced about 8 feet apart. However, they should be considered only as a stop-gap measure for privacy screens and windbreaks, as they are short-lived, being susceptible to a number of pests and diseases as mentioned above.
Name Origins and Other Kinds of Poplars
The tree originated in the Italian region known as "Lombardy," thus the origin of the common name. The nigra (Latin for "black") in the scientific name refers to the fact that its fissured bark can appear black from a distance. When specific cultivars such as "Italica" are not mentioned, Populus nigra is referred to simply as the "black poplar". The genus name, Populus means poplar tree.
Just as there are black poplars, so there are poplars in other colors. P. alba (alba is Latin for "white") is the white poplar (although it is also called the "silver poplar" sometimes), and P. canescens (canescens is Latin for "gray") is the gray poplar. Some types do not use "poplar" as a common name, for example, eastern cottonwood (P. deltoides). The common name "cottonwood" comes from the way this tree's seeds are dispersed. Cottony white hairs are attached to the seeds, which allows them to be blown far away from the parent tree where new plants will emerge. Some people may be more familiar with this mode of seed dispersal in the case of common milkweed (Asclepias syriaca).
Should You Grow Lombardy Poplar?
Although Lombardy poplars are despised by landscaping professionals, they remain a popular tree with the general public. They exert a fascination over many due to their unusual shape, and the speed with which they ascend to the heavens makes them hard to resist for the impatient.
The reason that Lombardy poplars are held in such low esteem by the pros is that they are short-lived (often succumbing within 15 years to the problems noted above). However, their short lifespan does not strip them of all value for the landscape. Here is a strategy to employ for a privacy planting that makes use of their fast growth rate while compensating for their tendency to decline rapidly:
- Plant a row of longer-lived screening plants (for instance, Colorado blue spruce trees or arborvitae trees) where you want your final "living wall" to reside.
- Then plant a temporary row of Lombardy poplars behind them (so as not to deprive the longer-lived plants of sunlight). The Lombardy poplars will soon be giving your outdoor space some privacy, while you wait for the longer-lived plants to reach maturity.
- To minimize the spread of the Lombardy poplars' roots, dig a planting trench for them and line its sides with a 40-millimeter, high-impact polyurethane barrier (as you would do to contain a running bamboo).
- Before the Lombardy poplar trees begin to deteriorate (and before their root systems become too well established), remove them, letting the longer-lived plants take over the job of screening out prying eyes.