Prickly Pete is the common name for Solanum rostratum, an annual plant also known as Buffalo Bur, Kansas Thistle, or Texas Thistle. It is widely distributed in disturbed areas like fields, roadsides, and pastures. It completes its life cycle in a single growing season, producing numerous seeds before dying.
Identifying Prickly Pete
This bushy plant grows 1 to 3 feet tall. Its branched stems are covered in sharp, yellowish spines, present even on young seedlings. The leaves are deeply lobed, resembling those of a watermelon, with spines along their veins and stalks.
Bright yellow, five-petaled flowers, 1 to 1.5 inches across, emerge in clusters in summer and fall. After flowering, a distinctive, round bur forms, densely covered in sharp spines. This bur, encapsulating the seeds, is a key identification feature.
Why Prickly Pete is a Problem
The sharp spines of Prickly Pete are a physical hazard for people, including livestock and pets. These spines can cause puncture wounds and may even damage vehicle tires.
Beyond physical harm, the plant competes aggressively with cultivated crops and pasture grasses for water, nutrients, and sunlight, leading to reduced agricultural yields. Its burrs can also contaminate harvested hay and wool, reducing their quality and value.
Prickly Pete contains solanine, a glycoalkaloid, making it toxic to livestock if consumed, particularly the foliage and green berries. While animals avoid the plant due to its spines, ingestion can cause illness. A single plant can generate up to 8,500 seeds, leading to rapid spread. Its spiny burrs readily attach to animal fur, clothing, or equipment, facilitating wide dispersal. Dried plants can also break off and tumble, scattering seeds like a tumbleweed.
Controlling Prickly Pete
Effective control of Prickly Pete involves a combination of methods, and timing is important.
For smaller infestations, manual removal by hand-pulling or digging is effective. Thick, protective gloves are necessary due to sharp spines. Remove the entire root system, ideally cutting the plant at least one inch below ground level. Dispose of plants before they set seed to prevent spread.
Chemical control is effective, particularly when plants are young and actively growing prior to flowering. Herbicides containing active ingredients such as 2,4-D, dicamba, or glyphosate can be used. Glyphosate is a non-selective herbicide, as it eliminates any vegetation it contacts, including desirable plants. Some herbicides, like carfentrazone-ethyl, are effective on plants at both early and later growth stages.
Preventative measures also help manage Prickly Pete. Maintaining a healthy, competitive vegetative cover, such as dense grasses, suppresses its growth. Regularly cleaning tools, equipment, shoes, and pet fur after being in infested areas prevents seed dispersal to new locations. Applying mulch in garden beds also suppresses seed germination, contributing to long-term control.