The Honey
locust (Gleditsia triacanthos) is a deciduous tree, widely
used as an ornamental because it grows quickly, transplants
easily, tolerates urban conditions, and provides nice shade.
Despite
its name, Honey locust is not a significant honey plant. The
name derives instead from the sweet taste of the legume pulp.
Growing
conditions
Tolerates
urban conditions (compacted soil, road salt, alkaline soil,
heat and drought), and transplants easily. Resistant to Gypsy
moths but is defoliated by the Mimosa webworm. Spider mites,
cankers, and galls are a problem with some trees. Prone to losing
large branches in heavy wind.
Uses
Pulp from the legume
was used by Native American people for food, and can be fermented
to make beer.
Its wood is high quality, durable and polishes well, but there
aren't enough to support a bulk industry. It is used for posts
and rails since it works with soil so well. A niche market
exists for honey locust furniture.
In the past, the hard thorns of the younger trees have been
used as nails.
Fun
Facts
A Native American legend
is that the Thunder Spirit recognized his son by his ability
to sit comfortably on locust branches, despite the thorns.
Not that there are
a lot of them in Evanston, but graze animals such as goats
and horses are particularly fond of the taste of honey locust
leaves, and apparently the leaves are good for them as well.
Size
Grows
quickly, 66-100 feet when mature.
Form & Shape
Oval, rounded
shape with a delicate, open silhouette that lets grass grow
underneath.
Bark
Honey
locusts commonly have 4-8" long thorns growing out of the
branches; these may be single, or branched into several points,
and commonly form into dense clusters. These thorns are fairly
soft and green when young, harden and turn red as they age,
and then fade to ash grey and turn brittle when they stop growing.
These may have evolved to protect the trees from now-extinct,
browsing Pleistocene megafauna.
Leaves
Pinnately
compound on older trees but bipinnately compound on vigorous
young trees (each leaf branches once or twice). There are 8-14
leaflets on each section, 1-2" long (smaller on bipinnate
leaves) and bright green. They turn yellow in the fall.
Flowers
The
strongly scented yellow or cream-colored flowers appear in late
spring, in clusters emerging from the base of the leaf axils.
Fruit
The fruit
is a flat legume (pod) that matures in the fall. The pods are
generally between 6-8" long. The pulp inside the pods is
edible and sweet.
Below is a schematic map of the Ladd Arboretum,
with a dot in red showing where the Legumes (including Honeylocusts)
are located. Click to take a virtual tour
of the Ladd.
