[3][4] The closely related species Salix atrocinerea Brot., which overlaps in distribution in France, Belgium, Netherlands, England and Ireland, is considered by some authors as the subspecies S. cinerea oleifolia (Gaudin) Macreight.

S. atrocinerea differs from S. cinerea in that it is taller (reaching up to 15 metres), has a deeply furrowed bark, dark red-brown hairs beneath the leaves, smaller stipules, and is earlier deciduous.

[6][7] Grey willow grows in wetlands, moist depressions, ditches, embankments, banks of stagnant or slow-moving water bodies, and forest edges, where it encounters low-lying damp situations with waterlogged and nutrient-poor soils.

[9] Salix cinerea is an invasive species in New Zealand and is listed on the National Pest Plant Accord, which means it cannot be sold or distributed.

S. cinerea is also highly invasive in south-eastern Australia,[10] with the entire genus listed as a Weed of National Significance.