Poplars are members of the genus Populus, which includes about 35 species of deciduous plants. They are also known as cottonwoods and aspen trees. Poplars include white poplars (P. alba), black poplars (P. nigra), eastern cottonwood (P. deltoides), and Balsam poplars (P. balsamifera), common aspen (P. tremula), and quaking aspen (P. tremuloides).
Poplars produce flowers in drooping catkins before the leaves appear. Their seeds are surrounded by abundant cotton-like hairs (which is why they may also be called cottonwoods). Bark on poplars is smooth and may be green, white or dark gray. The leaves often turn bright gold or yellow in the fall.
Poplars grow throughout North America, Europe, Asia and Africa. They prefer moist areas and often grow near water, often in river valleys and flood plains, but will not grow in woods.
Care and Planting
Poplars will grow in almost any soil, provided it is well-draining. It prefers a neutral pH and will not grow if the pH is above 8.6. They prefer spots that receive full sun and will not grow as well without it.
Pests and Diseases
Because of their smooth bark and soft wood, poplars are especially susceptible to cankers and fungus disease. As far as insects, poplars are often plagued by leaf-feeding caterpillars, leaf beetles, cottony cushion scales, mealybugs, scales, poplar-and-willow borer (Cryptorhynchus lapathi) and poplar petiolegall aphid (Pemphigus populitransversus).
Because they are fast-growing, poplars are often planted as windbreaks, especially the Lombardy poplar. Its soft wood is often used for paper. Because the wood does not shrink much, it is also commonly used to make floorboards. Matches are made from poplar because the wood burns slowly. Poplar wood is also commonly used to make clogs, packing boxes, and cotton-reels. The bark of poplar trees contains salicylic acid, an anti-inflammatory and analgesic agent, which makes it good for soothing burns, rashes, wounds, and limb pain.
A wide range of hybrid poplars are available because poplars hybrid easily. Hybrid poplars are usually crosses of either cottonwood (P. deltoides) or black poplar (P. nigra). Most hybrids retain the fast-growing properties of poplars but not their cold and drought hardiness. As such, they are often used as wind breaks and firewood.