How Long Does it Take a Lacebark Elm to Be Considered Mature?

Lacebark elm (Ulmus parvifolia) also sometimes is known as Chinese elm. Hardy in US Department of Agriculture zones 4 or 5 through 9, the tall shade trees are native to China, Korea and Japan. At maturity the elms reach 40 to 50 feet tall. Dr. Michael Dirr, Professor Emeritus at the University of Georgia, classifies lacebark elm's growth rate as "medium to fast," about 18 inches per year. At that rate, it would take at least 27 years to mature.

As they mature, lacebarks develop a spreading rounded crown that may be 25 to 40 feet wide. Mature specimens feature the "lace bark" that gives rise to the common name. Exfoliating in patches, the outer bark falls away to reveal combinations of gray, brown, green and orange bark underneath. The dark green leaves, which turn yellow in the fall, are serrate or toothed, with prominent veins. The foliage masks the insignificant red-tinged green flowers that appear in late summer. These are followed by samaras, or winged seed carriers that descend in the fall.

Dr. Dirr notes that the growth and maturation rate of lacebark elms is dependent on soil moisture and fertility. For optimal growth, nursery specimen should be planted in full sun in well-drained soil that receives consistent moisture. Young trees should be mulched to conserve that moisture. Mulch should not be allowed to touch the trunk, as dampness combined with microorganisms from the mulch can promote disease. Dutch elm disease, a severe problem for other elm species, does not trouble most lacebark elms.

Breeders have produced a number of lacebark selections, some of which are distinguished by an especially fast rate of growth. One of them, "Hallelujah" (Ulmus parvifolia "Hallelujah") also is noted for its excellent bark. "Ohio" (Ulmus parvifolia "Ohio") has a looser habit than the species and reaches a mature height of 40 feet tall in about 27 years. Another variety, "Burgundy" (Ulmus parvifolia "Burgundy") is described by Dr. Dirr as having "extremely fast growth," meaning that the tree grows at least 25 inches per year. The foliage differs from that of the species by turning red in the fall.

With its fast growth rate, beautiful bark, disease resistance, and tolerance for pollution and less than perfect soil, lacebark elm is an excellent street tree. Where there is sufficient room to accommodate its spreading habit, it also serves as a good specimen shade tree. The only downside to lacebark elm is that it succeeds so well that it is considered invasive in a few regions of the United States. Before planting, check with a local cooperative extension agent for information on the tree's status in a particular area.