Lily of the valley (Convallaria majalis) can be a beautiful ground cover around trees and in gardens, but it can be very invasive and spread quickly through your garden and lawn. Lily of the valley spreads underground with its extensive underground stem system called rhizomes. The stems then shoot up out of the ground and grow leaves and white flowers in the spring. Using topical weed killer does not kill the underground stems, which means lily of the valley will reappear and continue spreading throughout your garden and lawn. Getting rid of lily of the valley takes time but it can be done.
Getting Rid of Lily of the Valley
Use a shovel to dig around the lily of the valley shoots (the part of the plant above ground) and loosen the dirt around all of the lily of the valley.
Using your hands, carefully start pulling up the lily of the valley, making sure you pull up as much of the underground stem system as you can.
Throw away the lily of the valley you pulled up.
Using the tiller, till the dirt 6 inches deep where the lily of the valley was.
Spray the weed killer over the entire tilled area, making sure you get the soil completely wet with weed killer.
Check the area once a week for 3 months for any remaining stems growing up through the soil, and pull them immediately.
Follow the steps above to remove any lily of the valley that you don't want and keep the area of lily of the valley you want to keep intact.
Using your gardening shovel, dig a trench 6 inches deep by 2 inches wide around the lily of the valley that you want to keep.
Using a utility knife, cut a long-enough section of plastic border to place completely around the lily of the valley that you are keeping.
Insert the plastic border in the trench around the lily of the valley.
Take the soil you dug up for the trench and pack it in against the plastic border, covering it up until just the top protrudes from the ground.
The plastic border will keep the lily of the valley stems from spreading underground as the stem system is shallow and will be unable to penetrate the plastic border underground. Check the area every spring for any remaining lily of the valley growing out of the ground and pull immediately to prevent spreading. Many people love lily of the valley and are willing to take it off your hands. Put an ad in Craigslist for lily of the valley for sale. You will not only get rid of your lily of the valley, but you will make a little money too by selling it.
Lily of the valley is a poisonous plant and can be dangerous for small pets and children if ingested. If there are other plants near the area where you dug up the lily of the valley, use less weed killer and be careful when spraying it as it could kill the plants and flowers you don't want to kill.