Image 1. London planetrees . https://www.geograph.org.uk/photo/2619305
Scientific nomenclature:Platanus x acerifolia
Common Names: 'Bloodgood' and London planetree
Introduction:Platanus x acerifolia is not a native species to North America yet the origins from a hybridization of the P. orientalis found in European countries such as England and Spain and P. occidentalis American sycamore of North America. Platanus x acerifolia commonly referred to as a planetree or 'Bloodgood' and it has a wide ecological range from semi-arid zones to urban settings.Planetrees can range the entire country of the United States from east coast to west coast but rarely are found in the upper Midwestern states of Minnesota, North Dakota, South Dakota, Montana and Wyoming as shown in the shaded regions of image 1 . However, some of the Midwestern states are experimenting the trees adaptability to colder zones such as zone 4a in Minnesota.Full sunlight is required to grow and is highly drought tolerant.Soils where the planetrees grow range from clay, loam, and sand with either acidic or alkaline PH, and can tolerate extended flooding or well drained soils. Planetrees are commonly found in zones 5 to 9a.
Image 2. Range of the planetree in the United States shaded grey .
Site characteristics: The planetree prefers moist site but is very well adaptable to many different soils and does considerably well in urban conditions with root restrictions and air pollution. Since the planetree is versatile, site conditions could be minimally modified to accommodate optimal growing conditions. These trees grow well in acidic, alkaline, loamy, moist, sandy, well-drained, wet clay, and has some drought tolerance. The tree can tolerate cold hardiness zones from 4 to 9 which is a considerable portion of the United States. Full sunlight to partial shade is optimal growing conditions and needs just 4 hours of direct sunlight in a day.
Size and Maturity: At full maturity the planetree can grow heights of 70 to 85 feet with a crown spread from 50 to 70 feet. Crown shapes are often round, spreading, or pyramidal and can be very dense.
Life expectancy: Places in London, England have recorded the planetrees to be over 330 years old. There is no exact life expectancy as the planetree was hybridized in the later years of the 16th century and many of the trees from that time are still living.
Wood: Planetrees wood is similar to maples and has predominantly sapwood and very distinct ray flecks. The end grain is diffuse-porous with small to medium pores.
Leaves: Planetree leaves resemble the leaf of a sugar maple. The leaves of the planetree are 3-to 5-lobed and up to 9.8 inches broad. The leaf base is often straight with a margin that is smooth .
Uses: Planetree is used in many urban environments for its aesthetically pleasing looks. During the industrial revolution in London, England air pollution was potentially toxic which led to the planting of planetrees to control the air pollution. The leaves can be used to make great compost and the wood can be used for plywood, pallets/crates, furniture, and other small specialty wood objects. Primarily used as a long living shade tree in urban environments the planetree produces greenish flowers in the spring and is tolerant to urban pollution.The tree also produces seeds preferred by some finch bird species and squirrels.Historically planetrees has primarily been used in urban environments to combat air pollution.They are commonly found in open areas such as parks or larger yards and can also be used for avenues or along roadsides.
Reproductive details: Planetrees can be propagated either by seeding or cutting. Cuttings can be taken in the latter months of the year in the upper canopy which include at least the last two years of growth. The cuttings would then be planted in the spring and can grow very rapidly. This method has been proven to be a very successful method of propagation . Soil temperatures must be between 70-73 degrees F for proper propagation . Flowers appear on longer stems in the spring and become seeds which resemble ‘pom-poms’ and can be seen through the winter months. 'Bloodgood' planetrees are monoecious, which means they have separate male and female flowers on the same tree. Therefore, the “fruiting balls” usually occur in pairs and are formed from the fertilized female flowers. Image 2 is an example of a planetree fruiting, however, a single fruiting instead of the common paired fruitings.
Image 3. A single fruitling of the planetree . http://www.tree-guide.com/london-plane-tree
Maintenance: Planetrees are very low maintenance tree but can be pruned heavily to accommodate the spatial placement. However, the bark must be considered when placed into areas where aesthetics is important as the shedding bark litters the ground around the trees. Since the tree is very tolerant to several environmental conditions, not many maintenance practices must be considered. Image 3 provides a visual of the bark when it is exfoliating.
Image 4. A look at the exfoliating bark of the Plantree . http://www.missouribotanicalgarden.org/PlantFinder/PlantFinderDetails.aspx?kempercode=a892
Limitations: Planetrees are not suitable for smaller areas and requires a considerable amount of space to grow. This tree species is not particularly attractive in the autumn month as the leaves are a yellowish-brown color. Exfoliating bark can litter the areas around the tree which may not be ideal. In colder climate zones the tree is susceptible to frost cracking and may show leaf scorch on very dry summers. Canker strains in the 'Bloodgood' cause serious concern as the tree doesn’t compartmentalize the infection well. Two insects which cause issues with the development of 'Bloodgood' planetrees are the American plum borer and the sycamore lacebug. The hairs on the leaf’s fall off in the wind which can also be an irritant for people with respiratory issues.