Redstem filaree (Erodium cicutarium) is difficult to control due to its prostrate habit. It’s likely that a seed bank has built up over the years. This plant reproduces solely by seed. Management will involve integrated efforts toward eliminating seed production and depleting the seed bank. At the same time, you'll want to improve the vigor of the perennial grasses in the area. Consider overseeding with blue gramma (Bouteloua gracilis) or another grass to increase competition with the weeds. For other grass choices visit the Colorado Master Gardener Web site at www.cmg.colostate.edu for GardenNotes #571 – "Native Grasses."

Combine herbicide treatments with mechanical removal of rosettes and removal of seed heads from any plants that have flowered. Apply a broadleaf weed control product to the rosettes in early spring. Be sure to read the label of any pesticide product and follow its directions.