London plane

London plane

• Despite its common name, this tree is not a true Cockney - it is an introduced hybrid widely planted in London streets and squares. There are no native planes in Britain.
• It boasts a curious ancestry. It is a cross between two parent species brought together by man from widely separated regions - the Oriental plane from south-east Europe and the American plane from the United States - both imported to Britain as ornamental trees.
• The first botanical description in 1670 was of a specimen in the Oxford Botanic Gardens which probably originated from a nursery garden at Lambeth, South London where both parent trees grew and cross-bred.
• London Planes are hardy and stately, with a domed crown and thick twisting branches; they may grow to 30m (100ft).
• Both male and female flowers both grow on the same tree - the reddish female ones at the shoot tips, the yellow male ones further back.
• The bobble-like fruits, composed of many individual seeds, do not fall off but remain on the tree all winter - a further advantage where planes are planted in cities as they do not drop on people, cars or pavements.
• Most seeds are sterile so London planes are propagated by cuttings.
• Measuring about 15cm (6ins) across, the large light-green leaves have about five lobes. The foliage fades to a rich brown in autumn, falls and the leathery leaves slowly break down over winter.
• The timber is hard and fine-grained, resembling beech and is marketed as "lace wood" because of the delicate tracery of its grain pattern.
• The London Plane has been widely planted in parks, squares and avenues here, principally in southern England. It combines the beauty of its elegant form, shady but not gloomy summer foliage and attractive bark with the practicalities of coping with soot-laden air and restricted root spaces in built up areas.
• Additional pluses for urban use are that it thrives on most soils and withstands heavy pruning as well as pollution.
• The survival secret is that its shiny leaves are easily washed clean by the rain and it sheds bark regularly in large patches, preventing the trees lenticels or breathing pores in the trunk becoming suffocated under a layer of sooty, sulphurous grime.
• Many were planted 200 years ago and are still growing vigorously in London squares as they were one of the few trees that could thrive in the soot-laden atmosphere and inner city smogs.