Ulmus Thomasii, or more commonly know as Rock Elm, is a tree with green foliage and yellow flowers of the genus Ulmus. It has a moderate growth rate and a height of 95 feet at maturity. Its duration is perennial which means it will grow year after year. It's active growth period is spring and summer, blooms during mid spring, is somewhat tolerant of shade and is routinely available commercially. Ulmus Thomasii or Rock Elm's floral region is North America US Lower 48, specifically in the states of Arkansas, Connecticut, Iowa, Illinois, Indiana, Kentucky, Massachusetts, Maryland, Michigan, Minnesota, Missouri, North Dakota, Nebraska, New Hampshire, New Jersey, New York, Ohio, Pennsylvania, South Dakota, Tennessee, Vermont and Wisconsin.
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