Hemerocallis fulva (L.) L. (Family: Liliaceae)
The common daylily is not a true lily but is a popular garden flower, prized for its showy flowers, hardiness, and ability to spread. There are many cultivars of daylily (over 40,000 registered!) which come in a wide variety of sizes and flower colors. Common daylilies have a long life span, and their beds work well for erosion control. Unfortunately, the same characteristics that make them desirable in that setting make them an invasive species in others.
Also known as: orange daylily, tawny daylily, common orange daylily, roadside ditch lily
Origin: Common daylily is native to Asia and was introduced to the United States in the late 1800s as an ornamental, and it continues to be sold and planted as such.
Common daylily has round stems and can be 2-4 feet tall.
Basal leaves are bright green, smooth, sword-like, slightly folded in the center, 1-3 feet long, and curve toward the ground.
Flowers are large, 6-petaled, funnel-shaped, and typically orange, occurring at the ends of round stems in clusters of 5-9. Within a cluster, flowers open one at a time and remain open for one day each in June and July. Flowers may have stripes or spots.
Distribution: Throughout the United States, common daylily infestations occur adjacent to plantings from which they have escaped or at old home sites. They can also be found in natural or disturbed areas such as drainage ditches, floodplains, meadows, forests, and forest edges.
Problem: Common daylily spreads by rhizomes to form thick mats, which if left unattended can form large colonies over time and out-compete and displace other native vegetation. Gardeners may inadvertently spread common daylily by tossing away whole pulled plants. Once it is established, its thick tubers make control very difficult, as it is long-lived and persistent.
Control: To control common daylily beds, the entire root system of the plants with the tubers must be removed, or re-sprouting will occur. In the fall, use a spade or shovel to loosen the soil, dig up the root system, and then rake up and remove all plant parts. If you choose to use an herbicide, glyphosate (20% active ingredient) may be applied to cut surfaces after cutting the plants close to the ground, but this method will likely require follow-up treatments.
USE PESTICIDES WISELY: Always read the entire pesticide label carefully, follow all mixing and application instructions and wear all recommended personal protective gear and clothing. Contact your state department of agriculture for any additional pesticide use requirements, restrictions or recommendations.