What is Desmodium?

Desmodium is a perennial flowering plant that is a member of the Fabaceae or pea family. These plants grow along roadsides, open woods and in pastures throughout the southeastern part of the United States, as well as parts of southern New York and into eastern Pennsylvania. Tick trefoil, tick clover or beggar lice are other common names for this plant.

Considered a wildflower or weed, the desmodium may reach a height that is as tall as 6 feet (182.88 cm), though it will usually grow to a height that is much shorter. Plants have slender leaves that are dark green in color and grow as leaflets in groups of three. The flowers of the desmodium are typically pink to purplish-pink and grow to 0.5 inch (1.27cm) in length.

Blooms of the desmodium first appear in June and last through July or August. These blooms form at the end of long stems and may appear as either loosely- or tightly-packed clusters. Each of these flowering clusters may have as many as 100 blooms apiece of these small elegant flowers.

Although the blooms of the desmodium have only two petals, they play a significant role in the plant's pollination. When an unwitting insect lands on a flower to feed on the nectar, the petals briefly close over the insect and the flower shoots a spray of pollen onto the insect as a way to ensure pollination. After pollination occurs, the bloom reopens and allows the insect to depart.

Once this pollination occurs, the bloom drops off and a seedpod called a loment grows in its place. These pods have sticky hairs that attach to animal fur or clothing when they rub or brush against the plant. To assist in this distribution, the plant actually bends closer to the ground as it matures. This allows for a better chance for the seed to transfer onto a creature or human and travel elsewhere.

A favorite flowering plant for hummingbirds and butterflies, individuals sometimes use desmodium in flower gardens and landscaping. When started in an established garden, individuals should take care to place the plants in an area where they will not crowd out the other types of flowers that are already there. Considered highly adaptable, these plants are quite hardy and can tolerate a variety of soils. They prefer a soil that is more moist than dry, but as long as they have sun, the desmodium is happy.