PPDL Picture of the Week
March 13, 2017
Travis Legleiter, Weed Science Program Specialist, Purdue University
As the spring progresses, you will
start to notice that fields will start turning fairly pretty colors such as
bright purple and yellow. It is most
likely you will see this in no-till fields especially in southern Indiana. The weed that are responsible for turning
fields bright yellow is cressleaf groundsel, which is also referred to as
ragwort and butterweed.
This yellow flowering weed is
often confused with the mustard family because of its deeply lobed leaves and
yellow flowers. Upon closer inspection
it is much different than the mustards though and have several distinguishing
characteristics. Cressleaf groundsel is
a winter annual that emerges in the fall as a rosette and has the distinct
deeply lobed leaves, in the spring the plant bolts on a hollow stem, and
produces the bright yellow ray flowers.
The characteristics that set cressleaf groundsel apart from the mustards
include the hollow stem and the ray flowers.
The mustards will have a solid stem, will have four petal yellow
flowers, and have the distinctive silique seedpods that cressleaf groundsel
While cressleaf groundsel
typically does not compete directly with crops, as it is usually gone by late
spring due to its winter annual growth cycle, it can delay crop planting. As with many winter annuals, the dense
populations of plants in field keep the soil from drying and warming up causing
a delay in planting. The most effective
method of control is to apply a burndown in the fall when plants are
small. A burndown can also be applied in
the spring, although at this point the weeds have already produced seed that
will contribute to future generations.