Re-populating our poplar
Local botanist Nick Bertrand suspected a row of trees lining the River Ravensbourne in Ladywell Fields (the Middle Field) were rare native Water Poplars, Populus nigra subspecies betulifolia. Following DNA analysis, so they proved to be.
‘Water poplar’ is the old English name for our native black poplar, a term increasingly used today to distinguish the tree from other black poplar subspecies.
Four poplars were taken down during the recent park restoration project, seemingly for health and safety or access reasons. But 12 mature trees still border the river here.
Why so rare? To start, the tree is dioecious – male and female flowers grow on separate trees. OK for fertilisation in floodplain woodlands where trees grew close together but such woods have long been felled for farmland or buildings. However, planting individual trees in damp places continued, for the light, tough, springy timber lent itself to all sorts of uses.
But during the 18th and 19th centuries, faster growing, straighter hybrids were developed, supplanting the native tree. Cross-fertilising with the hybrids further diminished the original stock. Today, only a few thousand true water poplars survive in the UK, generally aging trees over 200 years old. Most are males – the preferred tree when propagating, as the females produce seeds with irritant fluff.
The specimens found in Ladywell Fields are all males and a strain known as the Manchester poplar – clones of water poplars much grown in that city for their resistance to industrial pollution. Likely enough the trees were purchased and planted when the park was created in the late 19th century.
Cuttings, or ‘truncheons’ as they’re known, have been taken and are being cared for at Creekside Education Trust’s site in Deptford where it’s hoped they’ll root. The search is on for suitable suitable sites along the Quaggy and other local rivers for re-establishing this magnificent wetland tree.
Perhaps a few water poplar indigenous to our area are still growing somewhere in the vicinity. But most specimens are likely to be hybrids. The two towering poplars in Sutcliffe Park have been identified as such. They’re both Populus X canadensis, created from crossing Populus nigra with an American species Populus deltoides.