London Planes (not only found in Gatwick...)

Kingdom: Plantae

Family: Platanaceae

Species: Platanus x acerifolia

Otherwise known as the London plane, Platanus x acerfolia is thought to be a hybrid of the Platanus orientalis (oriental plane) and Platanus occidentalis (American sycamore). This hybridisation took place in the 17th century, either in Spain or in Vauxhall Gardens in London, when P. orientalis and P. occidentalis were planted in proximity to each other. For a long time after its creation, the reason for how it was created remained a mystery, but the hybridisation is now a well acknowledged fact.

The hybrid is fertile and seedlings are occasionally found near mature trees.

Fun fact: The London plane was one of the 50 Great British Trees the The Tree Council selected in 2002 in honour of Queen Elizabeth's Golden Jubilee.

While it is visually very similar to the American sycamore, the London plane gets its name because it is planted almost exclusively in urban areas, whereas the American sycamore is found more commonly in lowlands and along streams. This is due to the species' tolerance to atmospheric pollution and root compaction, meaning it is suitable for urban roadsides. it also has high tolerance to winter conditions, and is wind-resistant. It is also tolerant (lots of tolerance here) to warm weather, making it a popular choice as a shade tree in Australia.

The London plane is a large deciduous tree which usually grows up to 20-30 m tall. It has a pale grey-green bark, smooth and exfoliating, with a camouflage pattern. Its leaves (when it actually has them) are large, thick and stiff-textured, and are palmately lobed with 3 to 5 main lobes, with the central lobe being the longest. They can cause a disposal problem in cities as they can sometimes take over a year to be broken down if they remain whole. The fruits are especially distinctive, which comprise a spherical cluster of achenes, with numerous stiff hairs which aid wind dispersal. The cluster slowly breaks down over the winter to release the numerous seeds. These can cause problems in urban use, as the short, stiff hairs are an irritant and can cause problems asthma sufferers.

London planes are often pruned by a technique called pollarding. Pollarding involves the removal of the upper branches of the tree, promoting a dense head of foliage and branches. This results in the tree being much shorter with stunted, club-like branches. This creates the shape that is sought after in urban areas such as main streets and plazas. Personally I think it looks a bit like a poorly decorated dead Christmas tree in Winter, but lets see how it looks in summer to see if there is any improvement.