Some gardeners love them and some gardeners hate them. If you are a gardener who despises native daylilies (Hemerocallis fulva), you may have a challenge ahead of you if you hope to get rid of these flowering plants. Digging up the daylily rhizomes does not usually remove the plant permanently as a new one can grow from the tiniest piece of rhizome left behind in the soil. Instead, smother the daylily plants under plastic and mulch to remove them for good.
Mow the foliage down to the soil level early in the spring so that as little foliage remains on the plants as possible.
Cover the entire daylily area with two sheets of thick black plastic sheeting. The plastic sheeting will prevent the daylilies from receiving both air and sunlight and should starve the daylilies of these necessary nutrients.
Cover the black plastic sheeting with a foot of straw or hay mulch.
Keep the area covered until the next spring and then remove the mulch and the plastic to assess the area. Pull up any foliage you find and dispose of it. If the growing area seems to be free of daylilies, cultivate the area and replant as desired. If you find surviving daylilies, repeat steps one through three to finish removing the remaining daylilies.