New weed in California – African spiderflower (Cleome gynandra)

Jul 20, 2018

New weed in California – African spiderflower (Cleome gynandra)

Jul 20, 2018

Dr. Mohsen Mesgaran, who joined the Weed Science Group this year as our weed ecophysiologist, found this plant growing on the research farm at UC Davis.

Slim seedpods with tiny seeds
Slim seedpods with tiny seeds
African spiderflower is a summer annual broadleaf plant in the caper family (Cleomaceae), growing up to 3 ft tall and wide. The flowers are white, somewhat tubular, with long red-to-orange stamens (see photos below). Interestingly, African spiderflower plants have three types of flowers - male, female, and hermaphroditic.

We have no idea how this plant got here. It is native to Africa, where the leaves are used as a vegetable; it is now widespread and invasive in many tropical to subtropical parts of the world. The USDA lists it as introduced in much of the United States southeast, from Texas to Virginia. Ellen Dean of the UC Davis Herbarium confirmed that the plant has not been reported in California before.

Mohsen and I pulled all the plants we found (a couple dozen or so), showed them to research farm personnel, and put the plants in the Plant Materials Bad Stuff dumpster for sterilization.

All photos are by Dr. Mesgaran.