London planetree and sycamore

Botanical name

Platanus x acerifolia (London planetree); Platanus occidentalis (American sycamore)

Type

Very large deciduous shade trees

Size

About 70 feet for London planetree (Utah State University); American sycamore 60 to 120 feet (USDA Forest Service)

Hardiness

Zones 4 to 9 (London planetree); zones 6b to 7b here

Where it is found

Old planted lots and streets on the valley floors, about 4,000 to 5,100 feet

Known weak points

Anthracnose leaf and twig drop, ice damage, sidewalk and curb lifting

Planetrees and sycamores are close relatives, and the names get used loosely. London planetree is the cross between American sycamore and Oriental planetree and is the one planted as a street tree in the West. This page covers how to tell them, where they grow in our elevation bands and what pruning, cabling or removal looks like.

How do you identify a London planetree?

The bark is the giveaway. Plates peel off in patches and leave a mottled pattern of tan, gray, green and cream. The leaves are large and maple-like with three to five lobes. The fruit is a ball of seeds hanging on a long stalk; Utah State University notes London planetree usually carries two or three to a stalk, while American sycamore usually carries one.

The seed balls persist through winter and break up in spring.

• Mottled, peeling bark in tan, green and cream
• Large 3 to 5 lobed leaves
• Spiky seed balls that hang through winter
• Two or three seed balls per stalk on London planetree

Where does it grow in Reno, Carson City and the Carson Valley?

It is a tree for roomy lots and wide streets on the valley floors. Reno (4,505 feet, zone 7b), Carson City (4,680 feet, zone 7a) and Minden (4,725 feet, zone 6b) are inside the species' rated hardiness range. Utah State University rates London planetree high for drought tolerance, which suits a place that gets about 7 to 9 inches of precipitation a year at the nearest NOAA stations.

The Nevada side of Tahoe sits at 6,200 feet and above (zone 6b to 7a), and the planted trees there are mostly conifers. The Forest Service lists American sycamore as susceptible to ice damage, which counts against it in snow country.

What goes wrong with it here?

Anthracnose is the usual leaf problem. Utah State University describes early-season leaf drop or twig dieback, with new leaves typically following and trees not severely affected. A planetree that looks ragged in May is not necessarily dying. The drought stress and dieback page covers how an arborist tells the causes apart.

Size is the other trouble. USU says the tree can overgrow a small site and break sidewalks and curbs, although less than lindens and maples. See tree roots, sidewalks and sewer lines. Large limbs carry real weight, and ice or wet snow can bring them down. It is rated not good under power lines.

Pruning, cabling or removal: which is the right call?

Deadwood and broken limbs can be taken out any time. Larger structural pruning belongs in late winter when the tree is dormant. Thinning and end-weight reduction on the longest limbs are the usual cuts; topping a planetree is not a fix, as this guide explains.

A sound tree with one weak union may be held together with cabling and bracing. Removal is the usual answer where there is decay in the trunk, a heavy lean that has changed, a large dead section, or roots that are damaging a house line or sewer. Planetrees are often large tree removal jobs and many need crane work.

What does Battle Born Tree Service do about a planetree?

The free estimate is where this gets decided. We assess the tree in person, and the arborist's call is one of pruning, cabling or removal. We hold a Nevada Business License (#20131580674) and are fully insured, and two of the eight crew members are ISA Certified Arborists (WE-11728A is one person's credential). For firewood, call the office about what is available.