Restricted Noxious Weeds 
Agronomy 105's Weed ID
Bitter wintercress
Bitter wintercress is also often referred to as Yellow rocket. 
It can grow either as a winter annual or a biennial and can sometimes grow as a perennial.  However, it reproduces only by seed.  This weed is a serious problem in Indiana and to our north and west.  In addition to small grain fields this weed may also be found in roadsides and waste areas. 
Bitter wintercress is a member of the mustard family and it has bright yellow flowers.  It can be distinguished from wild mustard in that it blooms much earlier in the season.  Another way to distinguish Bitter wintercress from Wild mustard is to look at the seed pods. 
The outline of the seed of Bitter wintercress cannot be seen through the pod whereas the seed outline is visible through the pod of Wild mustard.  The lower leaves of Bitter wintercress will be lobed and will have a very large lobe at the end of the leaf.  The seed of this plant is a dull, tannish to light brown color with a rough seed coat.  Bitter wintercress can be easily controlled by spring plowing because it seldom survives cultivation.  Mowing the weeds in May or early June is another effective means of controlling this species.