Pests Under Eradication: Camelthorn

Camelthorn is in the leguminosae (pea) family. It is somewhat like a woody brush that grows 1½ to 4 feet high.. Rootstocks have a tendency to branch, but usually after they are 3 to 4 feet deep. The rootstock system of Camelthorn can spread in all directions from a mother plant to a distance of 25 feet. Aerial parts start appearing in spring. The stems are armed with spiny thorns from ½ to 1½ inch long, arising from leaf axils. Leaves simple and entire, size varies from very small at the top of plant to 1 inch long below.

Flowering begins in June and fruits in July. Flowers are maroon, fading to violet, pea-like. The fruit is a slender pod, twisted in various forms. Seedpods are reddish-brown, constricted between seeds to resemble a string of beads, end the pod narrowed to a shot beak, indehiscent. Seed remains viable for many years.

Browsing animals have been a factor in disseminating Camelthorn. A large number of seeds have been found in droppings of both horses and cattle.

Camelthorn was first found in San Bernardino County in 1951 in Afton Canyon. It has also been found in Barstow near an abandoned rail road right of way.

The Department has been treating infestations of this weed since 1954. This weed is the only weed pest specifically listed in the Food and Agricultural Code as a public nuisance and mandates removal wherever it is found. One location currently remains with only one or two plants found each year. Treatments currently consist of manual removal of mature plants and chemical treatment of immature plants.