Hartwig Locust Tree - Robinia hartwigii
Fabaceae: Pea & Bean Family
USDA Hardiness Zone: 3


 

 
Hartwig Locust

Leaf: alternate, pinnately or bipinnately compound with 14 to 20 oval to elliptical leaflets each 3/4 to 1 inch long, overall leaf 6 to 8 inches long.
Flower: Greenish white flowers displayed in 2 inch long racemes, appearing after the leaves.
Fruit: Flat, brown, almost round pods, 1 to 2 inches long, each containing 1 to 3 seeds.
Twig: Slender to moderate, zigzag, grayish to red-brown, conspicuous thorns, lateral buds sunken.
Bark: Smooth, grayish brown, often mottled, lenticels present, later splitting.
Form: Small to medium sized tree to 50 feet with a spreading, open crown.


Leaves

The Fabaceae are herbs, vines, shrubs, trees, and lianas found in both temperate and tropical areas. They comprise one of the largest families of flowering plants, numbering 630 genera and 18,000 species. The leaves are stipulate, nearly always alternate, and range from bipinnately or palmately compound to simple. The petiole base is commonly enlarged into a pulvinus that commonly functions in orientation of the leaves (sometimes very responsively, as in the sensitive plant, Mimosa pudica). The flowers are usually bisexual, actinomorphic to zygomorphic, slightly to strongly perigynous, and commonly in racemes, spikes, or heads. The perianth commonly consists of a calyx and corolla of 5 segments each. The androecium consists of commonly 1- many stamens (most commonly 10), distinct or variously united, sometimes some of them reduced to staminodes. The pistil is simple, often stipitate, comprising a single style and stigma, and a superior ovary with one locule containing 2-many marginal ovules. The fruit is usually a legume, sometimes a samara, loment, follicle, indehiscent pod, achene, drupe, or berry. The seeds often have a hard coat with hourglass-shaped cells, and sometimes bear a u-shaped line called a pleurogram.

The native thorny locust species is found on both sides of the Mississippi River from Nebraska to Texas and from Pennsylvania to Alabama. Fence rows and pastures are common locations.

 


Hartwig Locust Bark
Being a member of the bean family, the Hartwig Locust is related to the Kentucky Coffee Tree and the vine Wisteria, among others.

Healthy, attractive trees add interest, pleasure, and value to landscapes. Some factors to keep in mind as you select a tree relate to your projected planting site and some factors relate to you. Healthy plants, growing under conditions that suit them, are marvelously engineered to deal with minor incidence of heat, cold, drought, storm damage, pests, and disease. Sometimes we unknowingly stress them, reducing their ability to stay healthy.

Trees provide cover: Birds and small animals need concealed places for nesting and hiding from predators. The presence of wildlife can make your backyard or woodlot a special place for your family and children. As urban sprawl displaces many birds and animals from their natural habitat, it becomes even more important for home and landowners to provide green space and mini-sanctuaries for birds and other wildlife.

Trees provide food: Having a wide variety of trees that provide seeds, nuts and fruit for wildlife to eat is one way to increase your success in attracting wildlife. although artificial bird feeders can supplement naturally occurring foods, they can attract unwanted pests such as pigeons, Canada geese, squirrels, and even rats. Trees also provide food by attracting insects and providing cover for their activities; mating, egg-laying. Insects form a huge portion of the warm-weather food supply for many species of songbirds.

And, most important in this age of man-made global warming, trees sequester large amounts of carbon dioxide.