Landscape and Turf - Perennial Weed Control

The following is information on perennial weed control in turf and landscape beds.

Perennial plants are the most difficult weeds to control in turfgrass and landscape beds because they have below ground reproductive structures that are difficult to remove by hand or completely kill with herbicides. These below ground structures have potential for regrowth to produce new plants in subsequent growing seasons. Several of these weeds, including thistles, dandelions, ground ivy and mugwort reduce aesthetics and functionality of these plantings. Fall is the most effective seasonal timing for non-selective herbicides such as glyphosate as well as selective turfgrass herbicides such as 2,4-D, triclopyr, dicamba and clopyralid used for broadleaf weed control. However, herbicide applications should be made prior to the first hard frost. As daylength becomes shorter in the fall, perennial plants begin to allocate sugars and reserves to below ground structures such as rhizomes, tubers, and bulbs. Physiologically, this allocation of plant reserves may improve the translocation of herbicides to belowground tissue to more effectively control perennial weeds.

Information from Dr. Stephen Hart, Extension Weed Specialist and Patrick McCullough, Program Associate, Rutgers