Lombardy poplars (Populus nigra 'Italica') are a member of the willow family. They are fast-growing trees and are often planted in rows and used as windbreakers.These broadleaf, deciduous trees are easily recognizable due to their distinguishing physical characteristics. Lombadry poplars also have a few undesirable growing habits and disease issues.
Lombardy poplar trees have a distinctive narrow shape. The trees are tall and thin, with diamond-shaped or triangular leaves. They can grow up to 40 feet but usually die before they reach their maximum height. The width of the Lombardy poplar tree averages 11 feet.
In the summer, the trees are covered with small, bright green leaves that make a pleasant sound when rustled by the wind. When autumn arrives, the leaves turn bright yellow. The branches of the tree are unusual in that they begin low to the ground and grow almost vertically parallel to the trunk rather than wide and horizontally.
Lombardy trees are known for their characteristically fast growth. The roots of the trees are shallow and can spread far and wide, even to the point of becoming invasive. In addition, the shallow roots can break sidewalks or driveways. The wood of the tree is weak, which causes limbs to snap off in ice or windstorms. Suckers are a huge problem with these trees and can sprout at the base of the tree or anywhere along the shallow roots.
One of the most well-known characteristics of the Lombardy poplar tree is the fact that it is highly susceptible to disease, most particularly stem canker disease. Edward F. Gilman and Dennis G. Watson, master gardeners for the University of Florida, do not recommend planting these trees in a home landscape at all for this reason. The disease kills the tree starting at the crown and works its way down, destroying the graceful shape of the tree in the process. Lombardy poplar trees are also susceptible to vascular disease, boring insects and leaf spot, which is a fungal disease.