Herbicide That Won't Kill Lilies

Before Planting

• Before gardeners plant their lilies, they must remove all weeds from the growing area. Using a herbicide that will not leave soil residue prevents killing your lilies at the time of planting. Spray your weedy planting area with a herbicide that contains glyphosate. Glyphosate kills weeds by inhibiting their ability to produce proteins. Wait 10 days to make sure the weeds are dead and that all herbicide residue has leached out of the soil before planting.

Grassy Weeds

• Grassy weeds like crabgrass, bluegrasses or even your own turf grass crowds out lily beds. Killing these grassy weeds without harming your lilies require selective herbicides. Selective herbicides are chemically formulated to kill grass species. Use a selective herbicide that contains fluazifop. Spray the herbicide away from your own turf grass. You can place a piece of plastic over nearby grass to prevent spray contacting and killing your lawn. Avoid using before rain or on windy days.

Broadleaf Weeds

• Broadleaf weeds are controlled by applying a pre-emergent herbicide before seeds have had time to germinate. Weed seeds germinate at different times depending on their species. For example, crabgrass germinates when soil temperatures reach 60 degrees while dandelion seeds germinate when temperatures are at least 50 degrees Fahrenheit, according to the University of California Integrated Pest Management. Pick a pre-emergent herbicide that contains trifluralin. Apply over the flowerbed area and water the flowerbed to allow the chemicals to sink into the soil.

Mulch

• Gardeners often use a synthetic mulch or geotextile around their lily's growing area to conserve soil moisture and keep weeds at bay. You can prevent weed seeds from growing on top of the mulch by laying down geotextile that has herbicides encapsulated nodules, according to the University of California IPM. Both the the herbicide and fabric keep weeds from popping up. Cut the geotextile to fit the planting area and secure the perimeters with landscape pins. Cut X-shaped holes in the fabric for planting lilies.