Gardeners with lily of the valley growing in a landscape fall into two categories: those who love this shady perennial plant and those who wish to remove it from their shady flower beds. If you fall into the second category, removing lily of the valley plants will be a challenge. This is because lily of the valley spreads (often invasively) by underground runners. You must remove every piece of these root runners from beneath the soil or they will grow into new lily of the valley plants.
Use the shovel to dig up the lily of the valley plants you have growing in the flower bed. As you dig up the plants, place them into the garbage bag immediately, making sure that every scrap of root from the plants goes into the bag.
Use the garden spade to cultivate the soil after removing the lily of the valley plants. It is essential to loosen the soil to enable you to find all of the pieces of remaining roots that are still in the soil.
Kneel on the soil and work through all of the dirt with your hands to find every piece of root that remains in the soil. Even the smallest piece of root left in the soil can grow into a new lily of the valley plant. Discard all of the roots in the garbage bag.
Apply glyphosate to the soil to eradicate any remaining lily of the valley roots and plants. Be very careful as you apply the glyphosate, however, because it will kill any plants it touches. Do not spray glyphosate on a windy day. Work the soil with the garden spade after applying the glyphosate so the chemical reaches down into the soil to eradicate remaining roots.
Repeat the digging and the glyphosate application one or two more times to remove the lily of the valley plants from your growing area completely.