Thursday, May 14, 2009

Landscape - Weed Control in Liriope Beds

The following is information on weed control in Liriope beds.

Liriope is one of the most common ground covers used in landscape plantings due to its durability and ease of care. As with all ground covers, weed management begins with planting in a weed free bed. If there are problem perennial weeds in the area to be established, two applications of glyphosate herbicide should be applied 3-4 weeks apart prior to planting. Once weeds have died, the area should then be tilled, planted and mulched.

In established Liriope beds, mulch should be replenished after mowing over the beds in late winter or early spring. Preemergence herbicides can be applied to Liriope beds in the late summer or early spring to prevent annual weeds from germinating. Materials labeled for one or more Liriope species (check labels) include include prodiamine, dithiopyr, isoxaben, pendamethalin, metolachlor, trifluralin, oryzalin, and benefin as well as combinations. For grass weed escapes in Lirope beds, fenoxaprop, clethodim, fluazifop-P-butyl, and sethoxydim are labeled for postemergence use for one or more species. Imazaquin can be used on Liriope muscari “Evergreen Giant” and “Silvery Sunproof” for control of some broadleaf and grass weeds as well as sedges and wild garlic pre and postemergence. It is strong on winter annuals and sedges. Bentazon is labeled for over the top postemergence control of certain broadleaf weeds and yellow nutsedge.

Spot treatments of gyphosate, glufosinate, or pelargonic acid can be made to weeds between liriope plants but care must be taken not to touch Lirope plants with the materials. In some cases the only option will be hand weeding.

Gordon Johnson, Extension Horticulture Agent, UD, Kent County.

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