Common plant names can create confusion

Historically, understanding and using the scientific names of garden plants has been the province of horticultural scientists and garden club lecturers. Many gardeners are intimidated by the language of nomenclature, those difficult-to-pronounce Latinized binomials, and most prefer using the common names, a preference encouraged by labeling at nurseries and garden centers. And most of the time, common names serve us well in our conversations with fellow gardeners about the plants we grow.

Yet common names also can be troublesome. A case in point is “red maple,” the accepted common name for Acer rubrum, a species of tree native to eastern North America from the swamps of Florida into Canada. In Maine, the bright red flowers of A. rubrum (“rubrum” is Latin for “red”) are harbingers of spring, both in the wild and in our gardens, and are the origin of the common name.

But in recent years, gardeners and garden centers have been using “red maple” to identify another tree, a cultivated variety of Acer platanoides (Norway maple) that has dark purple-red summer leaves. Suddenly communications break down.

A participant at a recent workshop told the following story. Searching for the native red maple for her landscape, she called the local garden center and asked if they sold red maples. Thinking she wanted the Norway maple, the garden center employee answered yes, they had several. She purchased and planted the tree in early spring, before the leaves emerged, and was both surprised and angry a few weeks later when the dark red leaves emerged!

This example is particularly troublesome because A. platanoides, including the purple-leaved cultivar, is a non-native invasive tree that has been shown to escape cultivation through dispersal of its seeds and displace our native sugar maples (A. saccharum) in natural areas. In other words, her new tree was a noxious weed!

Another potentially troublesome common name is “honeysuckle.” True honeysuckles belong in the genus Lonicera and the shrubby forms of Lonicera are the most serious invasive woody plant species in Maine, displacing native shrubs that are important sources of food for wildlife.

There is also a native shrub, Diervilla lonicera, which goes by the common name of Northern bush honeysuckle. The need for scientific names here is obvious. As I encourage gardeners to use the Northern bush honeysuckle and avoid the invasive shrubby honeysuckles, only use of the scientific names will avoid confusion.

Common names often are regional. Parthenocissus quinquifolia is Virginia creeper in Virginia, woodbine in New England. Liriodendron tulipifera is tuliptree in the North, yellow poplar in the South. Nyssa sylvatica, a large shade tree native to the Boothbay area of Maine, may hold the record for the most common names, including black gum, tupelo gum, sour gum, bee gum (one of the richest honey-producing trees in the world), upland yellow gum, snag tree, umbrella tree, swamp hornbeam, beetle bung, and hornpipe. If it were not for scientific names, such proliferation of common names would be the norm.

Note: For those interested in delving deeper, I recommend William T. Stearn’s Botanical Latin (Fourth Edition, 2004, Timber Press).

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