A Springtime Invader
Stephen Janak – County Extension Agent, Colorado County
We can be certain that our Texas spring is in full swing – all of the signs are there. Shade trees are starting to decorate their bare skeletons with light green fluff, fruit trees are hesitantly opening soft pink and white flowers, the first few bluebonnets are blooming on roadsides, and bastard cabbage is reaching its broccoli-like flowers skyward. You’ve probably seen this prolific invader blooming recently along county roads, medians, and in overgrazed pastures. Bastard cabbage, also known as ball mustard, wild turnip, or giant mustard, is scientifically named rapistrum rugosm. It is not a native of the U.S. or Texas. It was accidentally brought to North America from Europe, the Mediterranean, and North Africa. The problem with this plant lies in its invasive nature. As an annual plant, bastard cabbage requires sunlight for its seeds to germinate, and so it quickly colonizes bare ground and disturbed areas with a thick layer of dark green leaves and a deep root system. This allows it to out-compete native plants – including beloved roadside wildflowers – for sunlight, water, and nutrients. In many cases, bastard cabbage forms large colonies that exclude all other plants.
As a non-native plant, our native wildlife do not readily utilize bastard cabbage for food or habitat. Additionally, because of its spreading nature, it has begun to colonize wild areas, forests, prairies, and stream banks. Although maybe not apparent to us, if this pest continues to spread, it will have an effect on all ecological processes including providing clean water, abundant wildflowers, and good habitat for wildlife.
It seems like there is significantly less bastard cabbage along roadsides and in pastures this year compared to previous years. My only explanation for this is that with the abundant rain we received last year, grasses and other plants were able to grow, spread, and cover much of the areas that were left bare because of drought in previous years. Let us be thankful for that.
Bastard cabbage can be controlled by hand-pulling or chopping, although the taproot must be severed at least one inch below the soil to keep it from re-sprouting. Mowing can reduce the number of seeds produced, but is not a means of complete control. Herbicide options include 2,4-D, Dicamba, Chapparal, GrazonNext, and Cimarron Max. If you’re feeling adventurous or looking to save some money at the grocery store, the young leaves can be cooked like mustard greens and eaten. However you go about it, we should all do our part to control the spread and eliminate this invasive pest. For more information, call 979-732-2082.
Photos courtesy of Dr. Larry Redmon, Texas A&M AgriLife Extension Service
Additional photos can be found by searching “rapistrum rugosum”