Black and balsam poplar species and hybrids (PO)

Populus nigra, P. trichocarpa, P × canadensis, and P. × generosa

Native range

Black poplar (P. nigra) is a native species with a relict distribution along river valleys, mostly in southern Britain. Black poplar hybrids (P. x canadensis and P. x generosa)) have been planted on suitable sites across much of lowland Britain.

Provenance choice

The various clones have been produced through breeding programmes in mainland Europe and vary in their wood quality and resistance to pathogens (e.g. leaf rusts).

Site requirements

Generally cold hardy throughout Britain, but can be damaged by late spring frosts. Reasonably tolerant of exposure which explains the use of these species and hybrids in shelterbelts for fruit farms. Clones of P. trichocarpa are better suited to the cooler climate of northern and western Britain while the black hybrids are favoured by the warmer conditions in southern Britain. They require fertile soils, of rich to very rich nutrient status, with fresh to moist soil moisture but not waterlogged or dry conditions. Alluvial soils or deep rich loams are ideal.

Pests and pathogens

Poplar species and varieties can vary considerably in their resistance to cankers and leaf rusts (e.g. Melampsora larici-populina) which can cause both premature defoliation and death of susceptible trees. Specialist advice should be obtained to identify the most resistant clones.

Use

Climate warming may allow the use of clones that are currently not hardy in Britain. Specialist advice should be obtained on the best clones to grow in a given location.