By Mike Proctor
Characteristics: Cat’s claw sensitive briar is a warm-season, native, perennial forb with bright pink flowers and recurved spines (like a cat’s claw).
The leaves are bi-pinnately compound, having leaflets that split again into smaller leaflets. It grows as a sprawling vine up to several feet in length, but the stems die back to the crown each year. Schrankia uncinata and S. nuttallii are synonyms for this species. Pink Sparkles is another common name used in the horticultural trade. The tree commonly called “mimosa” is actually in a closely related genus, Albizia.
Area of Importance: Cat’s claw can be found throughout Oklahoma on dry prairies, often on poorer sites. Having a prostrate growth form causes some problems around tall, dense vegetation, so growing on less productive sites reduces the likelihood of the plant being shaded out by competitors.
Attributes: Cat’s claw sensitive briar is one of about 400 species in the genus Mimosa along with the common houseplant, Sensitive Plant. Most folks are familiar with the movement of plants in response to their environment, for example, growing toward the sun and out of the shade. This form of movement is called a tropism. Plants can exhibit phototropism in response to light or gravitropism in response to gravity, which is why stems grow up and roots grow down.
Other types of tropisms exist as well. Some members of the Mimosa genus exhibit a different form of movement called nastic. While still a movement in response to a stimuli, nastic movements happen rapidly. Venus flytrap is a good example of this movement type. Cat’s claw sensitive briar is capable of this movement type as well. The leaves will fold up in response to touch.
Opinions vary as to how livestock utilize Cat’s claw, but since I don’t see much of it in overgrazed pastures, I suspect they do eat it, probably when the stems are still young and tender.
As is the case with many members in the legume family, Cat’s claw forms root nodules where nitrogen-fixing bacteria convert atmospheric nitrogen into a form that can be used by the plant. This likely explains why the species is found on poorer soils; it has a nitrogen source that isn’t available to other plants on those sites.
While not necessarily contributing much to grazing resources for livestock, it does contribute nitrogen and organic matter to soils that need those components the most. Reports of wildlife use are limited to seed use by a few species of birds, including bobwhite quail.
The spines are really hard on shoestrings and hands, so when you go out in a pasture with Cat’s claw, you should probably wear boots and gloves.
For great videos on plant movements including Cat’s claw, visit www.plantsinmotion.bio.indiana.edu.