Weed-opedia: Parsley Piert
Parsley Piert (Aphanes microcarpa)
What does it look like?: A low-growing plant with inconspicuous green flowers. Many stems, and the leaves have three lobes, and each lobe is subdivided into three or four smaller lobes.
What causes it?: Closely mowed, nutrient-deficient lawns.
When does it show up?: It is a winter annual that sprouts in cool weather, but blooms in spring.
Best treatment plan: Thick, healthy turf is your best defense against this weed. Hand-pulling helps whenever possible. Chemically, a post-emergent herbicide applied diligently and most likely more than once, will work. Call a professional for a free quote.
How long will it take to get rid of it?: If you are diligent and the infestation is not too bad, a year or two should do it.