Bur Cucumber (Sicyos angulatus) is a rapidly growing annual vine belonging to the gourd family, Cucurbitaceae, native to much of eastern North America. This plant is known for its aggressive growth and the distinctive, spiny fruits it produces late in the season, which aid in its dispersal. While it belongs to the same family as edible cucumbers, Bur Cucumber is generally considered inedible by experts. The plant presents both physical hazards and potential internal health concerns that make it unsuitable for human consumption.
Recognizing the Plant
Accurate identification of Bur Cucumber is important, as it helps distinguish it from similar species. The vine features long, lanky stems that are light green, furrowed, and covered with fine hairs. It uses branched tendrils to climb over adjacent vegetation, often forming dense, tangled mats. The leaves are large, alternate, and broadly heart-shaped, typically featuring three to five shallow palmate lobes that give them a maple-leaf or star-like appearance.
The most identifying features are the flowers and the resulting fruit. Bur Cucumber is monoecious, meaning it produces separate male and female flowers on the same plant. The staminate (male) flowers are small, greenish-white, and bloom in long-stemmed clusters, while the pistillate (female) flowers are bunched together on a shorter stalk. These female flowers develop into the characteristic bur-like fruits, which are small, about a half-inch long, and covered in stiff, barbed prickles and long hairs. These spiny fruits grow in dense clusters of three to ten or more, which is a significant distinction from similar wild vines.
Consumption Safety and Health Hazards
The plant is a member of the Cucurbitaceae family, which includes common vegetables like squash and cucumbers. However, this family also includes species containing bitter, toxic compounds known as cucurbitacins. While specific toxicity data for Sicyos angulatus is limited, mammalian herbivores often shun the foliage, suggesting a natural deterrent or low palatability.
The primary danger is the physical hazard posed by the plant’s mature fruits. These small, burred fruits are covered in numerous sharp spines designed for seed dispersal. If the fruit is ingested, these needle-like spines can easily break off and embed themselves in the mouth or throat. This can lead to localized pain, irritation, and potential secondary infection.
Consuming any part of the vine, especially the fruit, can lead to digestive distress common with many wild gourds. Symptoms of accidental ingestion may include nausea, vomiting, abdominal cramping, or diarrhea. The combination of physical irritation from the spines and the presence of unpalatable chemical compounds makes Bur Cucumber an unsafe food source.
Ecological Context and Control
Bur Cucumber is an aggressive annual vine known for its exceptionally rapid growth and ability to cover other vegetation. It is native to eastern North America, but its invasive nature has led it to be classified as a noxious weed in several states and an invasive alien species in parts of Europe and Asia. The vine thrives in moist, fertile, and often disturbed areas, such as riverbanks, floodplains, ditches, and the edges of cultivated fields.
The plant’s aggressive vining habit is the primary reason for its status as a nuisance weed in agriculture. It can reach lengths of 20 feet or more, climbing and forming thick mats over crops like maize and soybean. The sheer weight and traction of the vine can pull down crop plants, making them impossible to harvest and causing significant economic damage.
The fruits are key to its spread, as the barbed burrs readily attach to clothing, animal fur, and machinery, effectively dispersing the single seed contained within each fruit. Effective control requires a season-long approach focused on preventing seed production. Since it is an annual, the plant dies each winter, but its seeds can remain viable in the soil for at least three years, creating a persistent seed bank. Management strategies in arable lands often involve deep tillage to bury the seeds, followed by shallow tilling to manage emerging seedlings throughout the growing season.