Honey-locust – Gleditsia triacanthos

Honey-locust trees are not native to North America’s west coast, where I hail from, and as I haven’t spent much time in the eastern or central US, I hadn’t seen one in the wild before. I first came across a honey-locust tree at the the Botanical Garden of the University of Hamburg (Botanischer Garten der Universität Hamburg) in Germany.

It is an imposing thing, with its tall, monolithic bole, many thorns swarming around the trunk in fiendish clusters. They are long, rigid, cruelly sharp, and difficult to break off. Certainly not a tree I’d like to stumble into unawares!

The flowers are small but sweetly scented, and especially on warm evenings, their perfume carries lightly on the breezes, or spreads languidly through the still air.

Its small, pinnate (divided into leaflets) leaves make a gentle and soothing rustling noise when they move. What a marvelous visual texture they have, particularly against a backdrop of plants with large, undivided leaves. The undersides of their leaves are ever so slightly paler than their tops, making them even more attractive on windy days.

Their fruit is in the form of thin brown pods, similar to those of the black locust (Robinia pseudoacacia) or other leguminous trees. These pods cling to their branches even when shriveled and dry, rattling in the wind like gentle maracas.

Range and Distribution

Honey-locusts are native to 31 states and two Canadian provinces. For a complete list of these, please see the Footnote (located after the references list at the bottom of this page).

They also grow invasively in Australia. Attempts to eradicate the plant in Queensland were largely successful, though the distribution of the plant continues to be monitored.

Chemical Compounds

• Some late 19th century sources claim that honey-locust leaves contains 6% cocaine, but a more recent 21st century test of several pods by two independent scientists has found no evidence to support this assertion.
• An alkaloid called gleditschine was found in honey-locust leaves in the late 19th century. It was been shown at the time to cause stupor and a loss of reflexive movement in frogs. I could find no research on its effects on humans, but considering the wide use of this plant as a food source, I would assume any such effects to be negligible.
• Another alkaloid, called stenocarpine, was discovered around the same time as gleditschine, in 1887. It was used as a local anesthetic.

Food Uses

• The raw pods, when ripe, were eaten by the Cherokee.
• The pod pulp allegedly tastes sweet and can be either eaten raw or made into a ‘poor’ brown sugar substitute.
• Young seedpods can be cooked and eaten, with the young seeds allegedly having a taste reminiscent of raw peas. The pulp of older seedpods, however, is said to be somewhat bitter in taste when cooked.

Beverage Uses

• The seeds were crushed and the pulp used by the Cherokee to make a beverage.
• Mature seeds can be roasted and used as a coffee substitute.
• The pods were also used as beverage. This was prepared by soaking them in water, sometimes with the addition of sugar.
• Beer can be produced by fermenting the sugary pulp in a process similar to that used for carob beans (Ceratonia siliqua). Some recipes apparently call for the addition of persimmon (Diospyros virginiana) fruit.

Medicinal Uses

• The pods were used by the Cherokee as an adjuvant and/or to sweeten the taste of medicine used to kill intestinal parasites (worms).
• Pods infused in water and drunk as a treatment for measles by the Cherokee.
• The juice of the pods is an antiseptic. This may be why the pods were considered to be a panacea, particularly for the complaints of children, by the Creek.
• As a treatment for indigestion, the Cherokee would eat the pods or make an infusion with the bark. The infusion would then be either drunk or bathed in.
• The pods were used to treat dysentery, but I have found no description of how they were prepared for this use.
• An infusion of the bark was drunk as a treatment for whooping cough by the Cherokee, while the Meskwaki used it to treat fevers, measles, and smallpox, though they believed it to be particularly useful against smallpox.
• A mixture of sprigs, thorns, and branches was infused in water and used as a bath to prevent smallpox by the Creek.
• An infusion of the twig bark was used as a treatment for severe colds by the Meskwaki. Similarly, an infusion of the roots and bark was used by the Rappahannock as a medicine to treat coughs or colds.
• The bark of honey-locust was mixed with the bark of other species (prickly ash, wild cherry, and sassafrass) and drunk as a ‘blood-purifying tonic’ or cough treatment by the Delaware.
• Some chemical compounds in the honey-locust can be used to treat rheumatoid arthritis.
• The leaves are currently being researched for potential use as a source of anti-cancer compounds.

Other Uses

Biomass Fuel

• The use of honey-locust pods as a biomass fuel is being researched. The pods are fermented for ethanol production.

Timber

• The Cherokee used the wood to make bows.
• The wood of the honey-locust is coarse-grained but dense, and is strong, shock-resistant, doesn’t shrink much when it dries, is hard, and takes a high polish. These characteristics make it popular with wood turners and furniture makers, although it should be mentioned that the wood does not glue well. It is also durable in contact with soil, and is relatively rot-resistant, which further increases the range of its popularity. It is used for pallets and crates, for fence posts, and for general construction, including interior trim and finishings. Historically, it has been used to make farm tools and wheel hubs. It also splits easily and makes for good firewood.
• Though the wood has a wide range of uses and applications, it is considered by the US Forestry Service to be “too scarce to be of economic importance”.

Nails

• The thorns of honey-locust were once used as nails for softer woods.
• I would imagine that the thorns were historically used as awls or needles, but I have not found any evidence to support this.

Erosion Control

• Honey-locust trees are effective at controlling erosion and are often planted for this purpose. They are known to colonize spoil banks in strip mines.

Windbreak

• Honey-locust is effective as a windbreak and is widely used in shelter belts.

Wildlife Forage

• As the name implies, honey-locust is an important source of nectar and pollen for bees. Despite having the name ‘honey’ and being a food source for pollinators, however, this name apparently comes from the sweet pulp of the pods, rather than from its use in honey production.
• honey-locust pods are eaten by a wide range of animals, including birds (crows, starlings, quail), rodents (gray squirrels, fox squirrels, rabbits), marsupials (opossums), and larger mammals (white-tailed deer).
• The bark of young honey-locust trees is a choice food for deer and rabbits in winter, when other food is scarce.
• Young, tender spring growth, including leaves and shoots, is eaten by deer.

Livestock Feed

• The pods are eaten by goats, sheep, hogs, and cattle, though cattle cannot digest the seeds when whole, and so derive only the nutritional value of the pods. The ground seeds and pods make a valuable high-protein cattle feed. Sheep and goats can digest the seeds when whole, and so the pods do not need to be pre-ground for them to get their full nutritional value.
• The young shoots and leaves of honey-locusts are eaten by grazing livestock.

Ornamental Use

• There exists a thornless honey-locust, which is popular as an ornamental tree. It does well even in arid conditions.

Etymology

• Gleditsia is named for Johann Gottlieb Gleditsch (1714-86) of the Berlin Botanic Garden.
• Triacanthos is derived from Greek and means ‘three-spined’.

References

• Moerman, D. (2009). Native American Medicinal Plants. 1st ed. Portland, OR: Timber Press. ISBN 9780881929874
• Moerman, D. (2010). Native American Food Plants. 1st ed. Portland, OR: Timber Press. ISBN 9781604691894
• Gledhill, D. (2008). The Names of Plants. 4th ed. Cambridge University Press. ISBN 9780521685535
• US Forestry Service page on honey-locust
• PFAF description of plant uses
• Australian government page on invasive honey-locust
• Good general information, particularly on compounds for medical applications
• General overview of plant growth habits, with an array of reference photos
• General overview of plant growth habits. Contains a list of popular cultivars
• Describes a modern attempt at honey-locust beer production
• Mentions use of honey-locust in beer production. Readers should be advised that there is a somewhat dubious limerick on the second page.
• Brief overview of honey-locust trees
• Technical information about the gleditschine alkaloid
• Missouri BG overview of the species
• Detailed description of the thornless variety

Footnote: States to which the honey-locust is native

US States

• Alabama
• Arkansas
• Connecticut
• Delaware
• Florida
• Georgia
• Illinois
• Indiana
• Iowa
• Kansas
• Kentucky
• Louisiana
• Oklahoma
• Maryland
• Michigan
• Minnesota
• Mississippi
• Missouri
• Nebraska
• New York
• North Carolina
• Ohio
• Pennsylvania
• Rhode Island
• South Carolina
• South Dakota
• Tennessee
• Texas
• Virginia
• Wisconsin
• West Virginia

Canadian Provinces

• Nova Scotia
• Ontario