The London planetree (Platanus × acerifolia) is a very large deciduous tree that is quite resilient in urban conditions. This hybrid tree resulted from a cross between two sycamore species: Platanus occidentalis (American sycamore) and Platanus orientalis (Oriental plane).
Like all sycamores, the London plane has bark that peels away in irregular patches to show creamy whitish-green inner bark. Its green leaves are around 4 to 9 inches wide with three to five lobes, and its fall foliage is a rather plain yellow-brown. Small flowers appear in clusters in the early spring, gradually ripening into fruit balls that turn brown in the fall.
|Botanical Name||Platanus × acerifolia|
|Common Name||London planetree, London plane, hybrid plane|
|Plant Type||Deciduous tree|
|Mature Size||75 to 100 feet tall and 60 to 75 feet wide|
|Sun Exposure||Full sun to part shade|
|Soil Type||Loamy, sandy, or clay|
|Soil pH||3.7 to 6.5|
|Flower Color||Red (female), yellowish-green (male)|
|Hardiness Zones||5 to 9, USA|
|Native Area||North American-Asian hybrid|
How to Grow
The London planetree most often is used in urban landscapes where a very large tree is desired. It has excellent tolerance for air pollution and is a common choice in large city parks and other public lands. It also works well for medians and planting strips because the roots can handle small spaces with soil compaction.
The tree readily grows in spots that have moist soil and plenty of sunlight. But its roots can damage buildings, sidewalks, and driveways, so choose your planting location wisely. Moreover, its massive size and messy growth habit from fallen leaves, twigs, bark, and fruit make the London plane unsuitable for all but the largest residential landscapes. The tree also can be an irritant for people with allergies.
Full sun is ideal for the London planetree, but it will tolerate partial shade. It requires a minimum of four hours of direct sunlight every day, but six hours or more is better.
Although it can adapt to most growing conditions, the London plane does best in rich, deep, well-draining soil. It grows in loamy, sandy, and clay soil types. And it can handle acidic and alkaline pH levels, as well as some soil compaction.
The tree has medium to high water requirements, depending on how much heat and sun it gets. It prefers consistently moist soil, but it does have some drought tolerance, as well. Mulch around its base can help to retain soil moisture, but if there is an extended period with no rain the tree likely will need a good soaking with a hose.
Temperature and Humidity
London planetrees grow rampantly in moderate climate regions around the world. The tree can be amenable to a particularly hot summer, as long as its soil remains moist. And it can withstand a harsh winter, though it might sustain some cold injuries.
Because London planetrees are often planted in areas with poor soil or limited space, they might end up lacking nutrients. If that's the case, feed the tree in the early spring and fall with a tree fertilizer, following label instructions. But if the tree is planted in a fertile area with room to spread, it likely won't require much fertilizer. Test soil samples to know for sure.
Left unpruned, the London planetree will grow very large. In general, it's recommended to prune diseased, dying, and dead branches in the winter. Furthermore, the tree's growth is often trained with a technique called pollarding, in which it is pruned to maintain short, club-like branches. To keep this unique shape, annual pruning is necessary. Another pruning style used with this species is pleaching, in which the branches are braided together to form a living fence.
Propagation is carried out either through cuttings or via seeds that break off and spread from its fruit balls. Grafting is used to preserve the traits of cultivated varieties.
Common Pests and Diseases
London planetrees are susceptible to the same anthracnose fungus that affects the American sycamore, but there are disease-resistant cultivars available, including 'Columbia' and 'Liberty.' Another fungus affecting this tree is canker stain, which can be fatal. Other cankers, leaf spots, and powdery mildew are also seen in the London planetree.
One of the most common insect pests found on London planetrees is the sycamore lace bug. Other pests include borers, scales, Japanese beetles, caterpillars, and mites.
The hybridization of the London planetree is thought to have occurred accidentally sometime during the 17th century in either Spain or London when the American sycamore and Oriental planetree were planted close to one another. Since then, several cultivars have been developed.
- 'Bloodgood' is one of the more popular varieties, growing around 60 feet tall and tolerating undesirable environmental conditions, including drought and poor soil.
- 'Columbia' sports dark green foliage and grows to roughly 50 feet. It resists mildew and anthracnose and can tolerate heavy pruning.
- 'Liberty' is a quick-growing variety with a pyramidal shape that reaches around 50 feet. It has a good tolerance for mildew, anthracnose, heat, and drought.
- 'Metzam' (or 'Metroshade') grows to a strong 70 feet. Another disease-resistant cultivar, its leaves emerge with a reddish cast but quickly become a lustrous green.
- 'Mirkovec' is a dwarf variety with a shrubby growth habit and unusual lobed leaves with pink, cream, and bronze coloring.