How to Grow and Care for London Planetree

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). A fast-growing tree, the London plane typically gains several feet in height per year. It transplants well and can be planted throughout the year.

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.

London Planetree Care

The London planetree is most often used in urban landscapes where a very large tree is desired to provide shade and an attractive accent. 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. Once established, the tree grows quickly and can live up to 400 years.

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. This large tree should be planted at least 30 feet away from homes or other structures, and not too close to sidewalks, walls, or fences. 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.

Light

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.

Soil

Although it can adapt to most growing conditions, the London planetree 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.

Water

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 at least every other week.

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.

Fertilizer

Because London planetrees are often planted in areas with poor soil or limited space, they might end up lacking nutrients. If that is 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 will not require much fertilizer. Test soil samples to know for sure.

Types of London Planetree

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.

Pruning

Left unpruned, the London planetree will grow very large. In general, it is 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 of several trees are braided together to form a living fence. This technique must be started with very young trees.

Propagating London Planetree

While success is not certain, it's often possible to propagate the London planetree with a cutting from a branch. Grafting is used to preserve the traits of cultivated varieties. It's best to start propagation during the early spring, when you can see new growth eyes, or buds, on the branches.

1. Use garden loppers to cut off a healthy branch that's around 10 inches long. Be sure the branch you cut has at least two or three buds or growth nodes, and clip the branch so that there's a growth node near the cut end.
2. Dip the cut end of the branch in a rooting hormone powder, and then push the cut end into a large container filled with potting soil, or directly into the ground where you want the tree to eventually grow.
3. Water the cutting frequently enough to keep the soil moist, but not soggy.
4. Often, the cutting will sprout new leaves, but the leaves will then fall off. Don't give up, as frequently the cutting will then sprout new leaves within two weeks. Once you see this happen, you know the cutting is developing roots.
5. If you are starting the tree in a container, transfer it to its permanent home in the ground once it's a few feet tall, which can take three to five years.

How to Grow London Planetree From Seed

If you aren't in a hurry, you can often get London Planetree seeds to sprout in your garden. Start by gathering up seeds from an established tree's fluffy seed balls, which drop in great quantities in the spring. Soak the seeds in water for 24 to 48 hours, and then spread them across seed-starting soil in a tray. Mist the soil to keep it moist, and place the tray in a spot with bright, but indirect sunlight.

You should see the seeds germinate within two weeks or so. Once the seedlings are a few inches tall, transplant them to separate containers filled with good potting soil, and place them in an outdoor location where they will receive direct sun for at least 4 hours each day. Water the seedlings to keep the soil moist but not soggy.

It might take a few years, but once your trees are a few feet tall, transplant them to a permanent home in the ground.

Common Pests and Plant 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'. Other cankers, leaf spots, and powdery mildew are also seen in the London planetree. In mature, healthy trees, these diseases may cause leaf loss, but are unlikely to seriously harm the tree. Removing any infected branches and dispose of fallen leaves and twigs.

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. Smaller trees can be treated with an insecticide spray, but such treatment isn't practical on large, mature trees. However, by keeping the tree healthy with regular water and fertilizer, it usually can easily withstand an infestation of these pests.

Common Problems With London Planetree

Due to the large size of this tree, some of the most common issues are damages caused by the strong roots. Over time, a London Planetree's roots can lift sidewalks, crack driveways, damage walls and fences, and crack or damage water or sewer pipes. For this reason, it's crucial to only plant this tree in a suitable location where it has enough room to grow and spread without contacting nearby structures, walkways, or pipes.