California Rape Sinapis arvensis

Charlock Mustard is a winter annual wildflower in the mustard family that has been present in the US since the 18th century. It is typically found in disturbed locations such as vacant lots, grain fields, along railroad tracks and other waste areas.  It is not considered a threat to native plants but may be more of a nuisance in a garden or crop setting.

It has 4-petaled bright yellow flowers that appear above medium green leaves.  The stems have downward pointing white hairs and red sections where the stems join up.  This trait distinguishes it from other plants in the mustard family.

The bristly leaves of seedlings have prominent veins.  They develop from a basal rosette.  Leaves on the lower portion of the plant are lobed and toothed while the upper leaves are alternate and may be stalkless to having a short stalk.  The leaves become smaller as they ascend the stem.  

Pollination is done by bees and flies.  

Many parts of the plant are edible.  The leaves can be eaten both cooked or raw.  While older leaves are somewhat bitter, the hot, young leaves can be used as a spicy flavoring in salads.  Like the young leaves, the seeds are also hot and can be added to a salad.  When cooked, the flowers have a flavor similar to cabbage or a radish.  They can also be used as a vegetable or garnish. 

The oils from the seeds are also used in the production of soaps and for the lubrication of machinery.

During the hot summer months when it is particularly dry, the leaves can wilt and the plant will become stunted.  

Its weedy tendencies have been known to be an issue in agriculture.  But modern day herbicides have pretty much eliminated or control the problems.

A host plant for the caterpillars of Evergistis pallidata (Purple-Backed Cabbage Worm Moth), Pieris rapae (Cabbage White butterfly), and Pieris protodice (Checkered White butterfly).

Insects, Diseases, and Other Plant Problems:  This plant hosts an ellworm that can destroy other plants or crops.  A nematode, it gets its name from its resemblance to an ell.  Barely visible to the naked eye, they typically feed on bacteria, fungi and other microorganisms, however, they can attack the root hairs of plants.  

Seeds that remain in the surrounding area are viable for up to 60 years.