Editing Populus alba (section)

== Hybridization ==
[[File:Lisboa June 2014-10.jpg|thumb|200px|Alley of grey poplars]]
White poplar hybridizes with the closely related common aspen ''[[Populus tremula]]''; the resulting [[Hybrid (biology)|hybrid]], known as grey poplar (''[[Populus × canescens]]''), is intermediate between its parents, with a thin, grey, downy coating on the leaves, which are also much less deeply lobed than white poplar leaves. It exhibits marked [[hybrid vigour]], reaching {{convert|40|m|ft|round=5|abbr=on}} tall and a trunk diameter over {{convert|1.5|m|ftin|abbr=on}}, much larger than either of its parents. Most grey poplars in cultivation are male, but female trees occur naturally and some of these are also propagated.<ref name=rushforth />