By Laurie Casey
Special to Tribune Newspapers
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Morton Euclid London planetree – Ovation (Platanus x acerifolia “Morton Euclid”) deserves applause, according to Kunso Kim, head of collections and curator at The Morton Arboretum. “It is among my favorite shade trees, with an exquisite, pyramidal shape and a dominant central trunk,” said Kim. The mottled brown, green and tan bark peels off in large plates, revealing patches of inner bark in varying shades of cream to white.
Another applause-worthy feature is its resistance to anthracnose disease, a fungus that blackens and distorts new spring leaves on many hardwood trees, including oaks, maples and ashes. The fungus thrives on American sycamore (Platanus occidentalis), defoliating the tree in early summer, stunting twig growth and forming clusters of slender stems, called witch’s brooms. Repeated yearly infections weaken trees and make them susceptible to other diseases and winter damage.
“We’ve seen very minor infestations on Morton Euclid London planetree, but nothing like what happens to American sycamore,” said Kim. That’s no accident. It was bred specifically for resistance to the disease.
Arboretum scientist George Ware crossed an American sycamore that had little anthracnose damage over 10 years with a disease-resistant Oriental planetree (P. orientalis). Hundreds of seeds were harvested, germinated and exposed to anthracnose. Morton Euclid stood out because it was attractive, vigorous and anthracnose-free.
A young Morton Euclid London planetree grows quickly, up to 3 feet per year. Plant it in a sunny spot with room for its extensive roots and mature 60-foot height and 50-foot spread. (By comparison, American sycamore grows to 150 feet high.) This excellent urban tree can handle soil that is alkaline, clay and compacted. It tolerates pollution and drought with aplomb.
For free advice about selecting a London planetree for your home landscape, or about treating anthracnose, contact The Morton Arboretum Plant Clinic by email at plantclinic@mortonarb.org, call 630-719-2424 or visit mortonarb.org/tree-plant-advice. Laurie Casey is a staff writer at The Morton Arboretum in Lisle.
