Locust Trees Helped America Win Wars, Grow Crops

It does not have the spreading majesty of a white oak, nor the reputation of the American chestnut. Unlike the maple, its fall color is not spectacular, and few homes have furniture made from its woods. Yet the locust tree (Robinia pseudoacacia) is a very useful hardwood with its own remarkable beauty. This native mountain tree has numerous practical applications and has long been respected by inhabitants of southern Appalachia.

Locusts, especially the saplings, are characterized by stout and piercing thorns scattered along the branches. Most mature locust trees have a rather ordinary silhouette, growing into an indistict vertical shape. A colorful variety of names are used in referring to the tree, yet all the terms apply to the same species. Since the bark turns darker with age, the tree is sometimes called “black locust.” “Yellow locust” is another common name, because of the golden color of the wood. Its often called “white locust,” too, due to the light-colored wood of young trees.

Although the locust’s natural range roughly corresponds to the Appalachians, the tree was carried beyond the mountains by Indians and colonists, resulting in a modern range covering a large portion of eastern North America. The Jamestown colonists encountered these naturalized trees in southeastern Virginia and named it for the Carob Tree or Old World Locust, which is resembles. The pulverized root relieved toothache when applied directly, and the Native Americans also chewed the root bark to induce vomiting.

A Natural Fertilizer

The locust is a legume, related to plants such a beans and clover. This relationship is evident in the fall when the locust flowers mature into seed pods. The pods look like overripe beans with three or four seeds encased in a brown shell about four inches long. Legumes have the ability to extract nitrogen from the air and deposit it in the soil. Thus, legumes make the soil more fertile. Early farmers took advantage of this trait and the fact that locusts are among the first plants to sprout in an area that has been cleared of trees. They would clear a plot of land, allow locusts to grow a few years to fertilize the soil, and then plow the ground for a crop.
Locust timber is very hardy with many practical uses. Cherokee Indians used the wood for bows and blowgun darts. The first Virginia colonists found that the tree made sturdy cornerposts in their houses. Locusts became an important material in the construction of ships, increasing the durability of the American navy in the War of 1812. Since colonial times the best fencing material in the Appalachians has been split locust posts, from the early settlers who constructed all wooden fences to modern farmers who use locust posts with barb wire. Locust is also first-rate firewood. It generates copious amounts of heat and burns slowly. Compared to other woods, locust firewood produces more BTUs than almost any other species, hickory being its only equal.

Tasty Blooms

The most striking feature of the locust is its blooms. Locust flowers form layered, cloud-like clusters on the tree, seeming to float among the leaves and limbs. The leaves have a wavy, frond-like appearance (the botanical term is ‘pinnately compound’), providing a perfect frame for the flowers. The tree usually blooms during the month of May, although the timing differs with elevation. The amount of bloom on a tree varies a great deal from year to year, with only scattered bloom clusters appearing most springs. Yet about five years or so, almost every limb on every tree is crowded with white flowers, as if covered with a thick layer of snow.

Because of locusts’ tendency to outpace other trees in the early stages of forest succession, the trees often grow in colonies. In heavy bloom years, such large natural orchards of locust trees present a spectacular scene of white hillsides. The flowers fill the atmosphere with a sweet aroma that can be detected far away.

A Honey Of A Tree

The flowers on a locust tree are as useful as they are beautiful. Locust blooms contain the raw material for a first-rate honey. Beekeepers praise locust honey as one of the best honeys produced. When the trees are in full bloom, honey bees will work locust trees almost exclusively. The result is a light, almost clear honey with a smooth, clear taste. The sourwood tree has a well-deserved reputation for producing excellent honey, but the less-famous locust tree is a worthy competitor.

Naturalist Doug Elliott has discovered other palatable uses of the locust bloom. He finds the blooms to be tasty in a salad or mixed with pancake batter and fried. Elliott even makes a drink using the flowers by steeping them in a pitcher of water, allowing the nectar to seep out and flavor the liquid.

Locust doesn’t provide the fancy furniture and fall foliage of other species, but its many practical uses — food, fencing, and fertilizer — have been greatly appreciated by Indians, early settlers and modern inhabitants of the Appalachian Mountains.

R. Kelly Coffee is a naturalist and photographer living in Boone, NC.