Platanus ×hispanica

Fast-growing tree with a long straight trunk. It is characterised by the bark that flakes off to reveal a light green to yellow-green underground and grey-green, dark green to brown loose flakes. The broad palmately lobed leaf has 3 – 5 sharply serrated lobes and is slightly hairy on the underside. In the autumn the leaves turn colour to a brownish yellow. Fallen leaves do not rot easily and remain on the ground around the tree. The spherical flowers hang in pairs (1 – 3) on long stems, where spiky fruit appears later. These remain hanging on the tree until deep into the winter. Plane trees are very resistant to hard surfaces but surface roots can push the surrounding paving upwards. Takes pruning extremely well, even in old wood. It is important to use a tree stake for support at the sapling stage. Young branches have a tendency to break and the tree does not stand up at all well to sea wind. The seeds of Platanus x acerifolia are arranged in spherical fruits. They often remain in the tree for a long time until the new flowers appear. There are various clones in circulation, which can vary in detail and hardiness.

The Secret History Of The London Plane Tree

Photo: Tubb.

The London plane tree accounts for over half of our city’s tree population. With such arboreal omnipresence it’s easy to overlook just what a distinctive tree this is. The sight that catches at eye level and will be familiar to most people is its khaki camouflage-patterned bark. This mottled mix of grey, olive and cream is pleasing on the eye and if you could imagine such a thing as a benign militia lining our city streets, it would surely look something like a procession of London planes.

Yet despite the tree’s ubiquity it was only ‘discovered’ in the mid-17th century by John Tradescant the younger in his famous nursery garden and ark in Vauxhall. And ‘discovered’ in the sense that there’s a possibility the tree did not exist before this time.

So why was London’s most popular tree so late on the scene?

London plane’s famous bark: Photo: Tributory.

Here we have to go into the tree’s family history. The London Plane is most likely a hybrid between the American sycamore and the majestic Oriental plane. It took a long time for these ‘lovers’ to meet — the two trees thwarted by growing on opposite sides of the globe. But it seems the voyages of the early modern period with routine collections of specimens being brought home led to the American sycamore’s journey from its native eastern America, and the Oriental plane from southeast Europe. The first account of the Oriental plane in Britain is found in William Turner’s 1548 book: Names Of Herbs. While the American sycamore perhaps arrived some 150 years or so later at the beginning of the 17th century.

Due to the height of the trees it is possible to peer into Berkeley Square from a distance. Photo: Anatoleya.

The London plane would then have hybridised when its ‘parents’ found themselves sharing the same space. There is some probability that this was in the very Vauxhall garden where Tradescant first found the tree since both requisite family members were indeed there.

But how did it go from interesting curiosity to the urban tree of choice lining so many of London’s streets? It was planted en masse at a time when London was black with soot and smoke from the Industrial Revolution and when population expansion forced greater urban planning. Taking a cue from the plane-lined boulevards built in Paris from around 1850, the tree flourished in London due to its hardy characteristics.

Pollarded planes in John Islip Street. Photo: Jim Linwood.

Take that camouflage bark, for instance, it’s more than just an accidentally attractive quality. It has that pattern because the bark breaks away in large flakes in order that the tree can cleanse itself of pollutants. It also requires little root space and can survive in most soils. True, it grows to some 30 metres tall so when trees line a street they can cause problems for London buses and overhanging wires. But then it’s also an unusual tree in that it can flourish despite pollarding (the pruning of branches that often gives the tree a club-limbed appearance). The rather beautiful maple-like leaves, shaped like a five pointed star, also have an otter-like sleekness. The daily London grime simply rinses away, leaving the leaves a lush green.

The plane’s canopy of leaves. Photo: Andrea Kirkby.

However, the plane does maintain many of its ornamental qualities too. The best place to view the tree is perhaps Berkeley Square. Here the 30 or so examples were planted in 1789 and are among the oldest in London. What’s more, due to the height by which the branches expand into a canopy like structure, Berkeley Square is one of only a few where it’s possible to peer into the square from a distance (usually while attempting to cross the Mayfair streets).

Photo: Nigel Bewley.

The one real negative quality is for allergy sufferers, who must be wary of the spores released from the tree’s fruit. But those that don’t have this to consider will find these comical little baubles another pleasing quality.

All in all it is a tree that can be said to be a true Londoner born and bred, to the extent that it even took the city’s name.

For more on the London plane try The Great Trees Of London (Time Out) and The Trees That Made Britain by Archie Mills.

The London plane tree is able to withstand the many assaults of urban life. It is often found squeezed tightly into tree pits surrounded by impermeable asphalt and concrete, making rain absorption difficult. Despite their potential size when fully grown, the trees adapt remarkably to cramped quarters, even while overshadowed by buildings and other structures. Often, they are pruned to within an inch of their lives to fit under phone lines or to avoid streetlights. They survive not only runoff from salted roads but also a consistent barrage of raw fertilizer by neighborhood cats and dogs.

And yet the London plane is everywhere throughout New York City. In fact, the last Street Tree census conducted by the city’s Department of Parks and Recreation found that more than 15 percent of all street trees were London planes. They are far more than just pretty plants; these trees provide energy savings and measurably improved air quality — to say nothing of the acres of valuable habitat they provide for people and animals alike.

Image London planes are frequently mistaken for sycamores, as both have smooth grayish brown bark, which exfoliates to reveal a tan or pale green trunk beneath.Credit…New York City Parks Department

It is interesting to note that the London plane tree is actually a hybrid between two tree species, the American sycamore (Platanus occidentalis) and the Oriental plane tree (Platanus orientalis). The tree looks enough like its American parent that it is frequently mistaken for a sycamore, as both have smooth grayish brown bark, which exfoliates to reveal a tan or pale green trunk beneath. The basic explanation for this unusual adaptation is the bark’s lack of elasticity; it cannot expand as rapidly as the tree inside it does. But this peeling bark is a useful adaptation, which helps to eliminate harmful insects and parasites. Though the tree may look as if it suffers from a bad sunburn, the patchy, peeling bark actually works in its favor.

London plane-tree

About this hybrid

For many years after the London plane-tree was discovered in London, England, its origins were shrouded in mystery. It was originally thought that London plane-tree was a natural variety of Oriental sycamore, Platanus orientalis, an introduced species from Asia, however it was never observed growing in the wild. It is now accepted that London plane-tree is in fact a hybrid between Oriental sycamore and the North American sycamore (Platanus occidentalis). Some botanists speculate that this hybridization occurred in the 1600s when a gardener to Charles I of England planted seeds of American sycamore that had been collected in Virginia. It is thought that one of these American Sycamores subsequently crossed with an Oriental sycamore growing nearby. Since that time, London plane-tree has been cultivated for planting in cities around the world and it is now one of the most widely planted urban trees.

Derivation of names

The genus name Platanus, is the classical name for the plane tree, from the Greek platus, meaning broad, in reference to the wide leaves. The species name, acerifolia, means maple leaf, in reference to the shape of the leaves. The symbol x in the Latin name indicates that London plane-tree is a hybrid species.

Related species

London plane-tree may be distinguished from the closely related American sycamore by the number of fruit clusters, and the bark. London plane-tree typically bears its round fruit clusters in groups of 2, while American sycamore usually bears solitary fruit clusters. American sycamore retains more of its flaky outer bark than does London plane-tree.

Similar species

London plane-tree leaves are similar to maple leaves because they are both palmately lobed. However all sycamores, including London plane-trees have alternate branch and leaf arrangement, while all maples have opposite branching. Sycamores have 3 main veins while maples such as Norway and sugar have 5 or 7 main veins. In sycamores, the leaf stalk encloses and hides the bud on the twig, while in maples, the bud is visible in a groove at the base of the leaf stalk. Sycamores bear round fruit clusters while maples produce winged keys (samaras). Sycamore maple (Acer pseudoplatanus), not a sycamore but a maple, is so named because it has similar leaves and multi-coloured flaky bark.

London Planetree: A Tough Dweller with a Confusing Past

“Anyone who measures the height of two London planes at Bryanston, Dorset, will assume either he, or his hypsometer (a measuring device), has gone barmy,” writes Thomas Parkenham in his book, Meeting with Remarkable Trees.

Parkenham’s humorous enthusiasm is directed at two magnificent London planetrees “girthing” at 16 and 18 feet. He says that their massive trunks give them “such graceful proportions that they rise effortlessly from the ferny track, as though there was nothing in this achievement and British woods were stuffed…full of trees 160 feet high.” Instead, they are Britain’s two tallest hardwoods.

Not only do the London planes, as they are sometimes called, tower over the beeches, oaks, lindens, and ash that make up their neighbors, they have the distinct advantage of being able to withstand air pollution and other stresses of urban life better than their native associates. It is the quality that has made the London plane as popular with U.S. city foresters as it is with tree lovers in England.

London planetrees are not a species, but rather the result of a cross between two species from widely divergent parts of the globe. The parents are both the Platanaceae family, a far-flung group with one species native to Southeast Europe through northern Persia, one in Indochina, seven found in southwest North America and Mexico, and our common sycamore of eastern United States. The two that were (and still are) crossed to produce London planetrees are our very own American sycamore (Platanus occidentalis) of southeast Europe and the eastern Mediterranean region.

How this happy combination took place, unfortunately, is lost to time. One popular story is that the union occurred in John Tradescant’s garden. He was the gardener for Charles I and is known to have visited eastern America three times in the mid-17th century. Others doubt that his transplants would have been large enough to bear flowers and have seeds. The doubters claim that the hybrid was created in Spain. In fact, this tree is sometimes referred to by a name suggesting that region — Platanus x hispanica. Regardless of its origin, the new offspring of the cross was discovered to tolerate the nastiest of smoke and grime in London. Because of this, its fame spread and for 300 years it has been produced by nurseries that supply trees to cities throughout the moderate climate regions of the world.

What’s in a Name?

London is where the city-tolerant features of London planetree were discovered, but where does the “plane” come from? There is some argument among authorities about the intended meaning, but the word itself is from the scientific name of the genus, Platanus, which comes from the Greek word platys. This apparently means “ample,” but whether it referred to the spreading branches and shady foliage of this tree or its large, broad leaves, no one is sure.

Whatever the meaning, London planetree is sometimes erroneously referred to as sycamore (a name better applied to one of its parents, American sycamore) or simply plane tree.

In the Landscape
The London planetree is a widely planted street tree, and for good reason. The tree was found to thrive in sooty air and provide wonderful shade. Its ability to withstand air pollution, drought, and other adversities assures its popularity as an urban tree (hardiness zones 5-9). Strong limbs also help make the London planetree a good choice where site conditions allow for its large size.

Beyond its reputation as a survivor, this tree is simply worth admiring. The unique bark and interesting branching give it amazing visual appeal. It’s towering height (75-100 feet) makes it ideal for shade and cutting energy costs.

Read Norway Spruce: Loftiest on the Continent.

London Planetree

Bark of London Planetree
G. Lumis

Leaf of London Planetree
G. Lumis

London Planetree
G. Lumis

Scientific Name: Platanus acerifolia

Summary
Foliage: Deciduous broadleaf
Height: 75 to 100 feet
Spread: 65 to 80 feet
Shape: Spreading

Large green leaves have no effective fall color. The ornamental bark flakes off, exposing white, smooth bark underneath.

Plant Needs
Zone: 5 to 8
Light: Partial shade to full sun
Moisture: Wet to moist
Soil Type: Sandy, loam, or clay
pH Range: 3.7 to 6.5

Functions
Suggested uses for this plant include shade and specimen plant.

Planting Notes
Transplants readily. Tolerates wide range of conditions, including air pollution. Plant in a location that will allow the plant ample room to spread. Do not plant where branches will interfere with power lines.

Care
Bark and leaves continuously drop off, causing litter. Tolerates heavy pruning. Prune in the winter.

Problems
Some problems include cankerstain, anthracnose, lacebug, and frost cracking of the bark.
London Planetree is a better choice than the native American Sycamore (PLATANUS OCCIDENTALIS) because of its resistant to anthracnose.

Alternatives
Consult local sources, including historic or public gardens and arboreta, regarding cultivars and related species that grow well in your area.

Cultivars of PLATANUS X ACERIFOLIA
`Bloodgood’ is faster growing and more resistant to anthracnose than the species.

The most striking feature of the London Planetree is its flaking bark that peels to reveal a lighter colored bark underneath. Best used only in open areas where its growth will not be restricted.

Most Popular

London Planetree

FAMILY: PLATANACEAE

About London Planetree at OSU’s Landscape Plants site

  • Reputed to be the first garden hybrid; originally in King Charles I of England’s garden in 1663. Parents are American sycamore and Oriental planetree. The king’s gardener planted these two close enough together to produce progeny.

  • Heights can reach >150’ with a circumference >30’.

  • Leaves somewhat resemble classic maple and can be up to 9” wide.

  • Flowers are small; fruit in balls (1-2”), usually 2 in chain.

  • Bark is mottled and exfoliating. The trunk of older trees has large, warty bumps here and there.

  • Common in Portland.

  • #2 was planted beside the Sylvester Farrell house in 1880.

Tree # Location Dimensions Photo and Notes
2

Northwest Corner of SW Park & SW Main St
Right Of Way

63′ Height
95′ Spread
14′ Circ.

This tree was planted beside the Sylvester Farrell house in 1880.
40

1816 SE 21st Ave
Private, Front Yard

60′ Height
84′ Spread
17.7′ Circ.

164

1728 NE Stanton St
Private, Front Yard

82′ Height
85′ Spread
15.4′ Circ.

218

2024 SW Howards Way
Private, Front Yard

70′ Height
50′ Spread
9.7′ Circ.

This tree is in a courtyard adjacent to the street.
269

2407 NE 18th Ave
Right Of Way

73′ Height
90′ Spread
16.7′ Circ.

This is the south tree in a pair of Heritage Planetrees at this location.
270

2407 NE 18th Ave
Right Of Way

65′ Height
70′ Spread
14.4′ Circ.

This is the north tree in a pair of Heritage Planetrees at this location.
313

2437 NE Regents Dr
Right of Way

60′ Height
81′ Spread
16.5′ Circ.

This tree is on NE 25th Ave.
338

3967 N Overlook Blvd.
Right of Way

79′ Height
99′ Spread
12.8′ Circ.

This tree is in the NW corner of the pocket park.
339

3967 N Overlook Blvd.
Right of Way

65′ Height
87′ Spread
15.6′ Circ.

This tree is in the NE corner of the pocket park.
340

3967 N Overlook Blvd.
Right of Way

69′ Height
103′ Spread
17.6′ Circ.

This tree is on the S corner of the pocket park.
341

1335 N Mason St.
Right Of Way

69′ Height
90′ Spread
12.8′ Circ.

Platanus acerifolia ‘Columbia’

A Bit More

Platanus acerifolia ‘Columbia’ brings the beauty of the London Plane tree without the worry of anthracnose (symptoms include discoloration and leaf drop) or mildew to the landscape. This circa 1970 variety is a hybrid between Platanus occidentalis and Platanus orientalis. ‘Columbia’ was developed in 1984 to resist the diseases that so often plagued Platanus acerifolia. A strikingly beautiful tree with an erect growth pattern, it grows quickly and can reach 30 feet in 12 years or 50 feet in 25 years. It will spread about half as wide as it is tall. Five-lobed medium to dark green leaves are a nice foil to the handsome peeling bark that is gray-yellow to gray-orange when new and gray-green with age. Come fall, the leaves turn yellow and drop allowing a better view of the fascinating bark patterns. Its fruit balls are spiky spheres. This is a fabulously adaptable tree is unfazed by soil type, smog, heat, or disease. It can best be appreciated given room hence parks, lawns, golf courses and industrial parks are common applications. Best in Sunset Western Garden zones 2-24, it will be happiest in full sun with moderate water and deep rich soil. Boething Treeland Farms grows it in 15 gallons, 24” and 36” box sizes.

Platanus x acerifolia

(London Plane)

Although not native, Platanus x acerifolia is a common sight throughout the country, particularly in cities. It is a large, impressive tree often growing up to 30m in height. The most identifying feature is the grey bark which sheds in large plates leaving patches of pale green and creamy yellow fresh wood underneath. It does this as a response to pollution which can clog the pores of the bark.

Its leaves are large, thick and palmately lobed, closely resembling the leaves of a maple. When young, they are covered in thousands of fine hairs which fall off as the leaf grows. These hairs can sometimes be an irritant when carried by the wind, particularly to people with breathing difficulties. In Autumn, the foliage turns yellows and oranges before falling.

Flowers appear as small balls on long stems in Spring, maturing to produce the ‘pom-pom’ seed heads which can be seen on the bare branches in winter.

London plane is the ideal tree for urban locations for many reasons. It is tolerant of pollution, soil compaction, drought and heavy pruning, often being pollarded as shown overleaf.

” Back to the Tree Fact File

Platanus × hispanica (syn. P. × acerifolia)
London plane

Winter profile of London plane in White Plaza in front of Tresidder Union, with semi-deciduous Chinese elms in the background. Sairus Patel, 17 Dec 2018 London plane leaf. John Rawlings

This popular street tree is supposed to have originated in England in the 17th century as a hybrid between the American buttonwood (Platanus occidentalis) and the oriental plane of the Mediterranean. One of its virtues was that soot-encrusted bark flaked off each year. It was introduced to America in colonial times and was the tree adopted for planting on Market Street, San Francisco, after much controversy, and on University Avenue, Palo Alto, where it replaced the glossy privet. There are many hundreds on campus. One group is on Santa Teresa Street around Lagunita Court dormitory, and another in front of Roble Gym. On Galvez Street adjacent to Memorial Hall, one can see remains of a 1938 plantation. Another extensive group is north and west of Frost Amphitheater. London plane is widely used as a street tree in Palo Alto; one of the most beautiful is at 1250 Lincoln Avenue.

London plane trunk. Hailen Mak

The London plane is famous for its reliability; since these groupings are planted in a regular manner it is easy to conclude from their almost universal survival that, indeed, the performance bears out the repute. Landscape architects dealing with trees less likely to survive to maturity, like to group them artistically in irregular triangles and pentagons; should one succumb, the defunct stump is eradicated and the outcome is still artistic. The old campus plantings and those on University Avenue used seedlings. El Camino Real was planted with ‘Bloodgood’, which has proved to be susceptible to sycamore mildew; this causes the leaves to turn yellow and drop off during the summer. ‘Bloodgood’ continues to be used and in 2012 six individuals were planted around the John A. & Cynthia Fry Gunn Building (SIEPR).

London plane fruit. John Rawlings

London plane tree leaves are generally five-lobed and, if anything, the leaf teeth are coarser and the lobes not as deeply cut as those of the California plane, Platanus racemosa, but the main distinguishing feature is the absence of leafy green stipules at the base of the leaf stalk. Some maples, genus Acer, also have similarly lobed leaves (bigleaf maple is a good example). However, all the main veins to maple leaf lobe tips start from a single point at the base of the leaf; see this venation pattern illustrated and distinguished from that of London plane tree in the Maple photo gallery. The careful observer will notice another significant difference between Platanus and Acer, namely, the branching and leaf arrangement of maples is opposite, while that of plane trees is alternate.

The pendant seed balls are about an inch in diameter. By the time the seed balls litter the street, the light-weight seeds have already been forced out into the air currents by a release mechanism depending on the drying out of the packing, which consists of fine hollow straws.

Along with oaks and olive, Platanus is a significant allergenic tree in our area pollinating in April–June.

About this Entry: The main text of this entry is from the book Trees of Stanford and Environs, by Ronald Bracewell, published 2005. John Rawlings subsequently added the comparison to Acer and the note on allergy (Hailen Mak, MD). Scientific name updated from P. × acerifolia to P. × hispanica Oct 2017 (SP).

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