Olivia Kwong, PCA

Common Daylily

Hemerocallis fulva (L.) L.
Lily family (Liliaceae)

Origin: Asia

Background
Common or orange daylily was introduced into the United States in the late 19th century as an ornamental. It is a very popular plant favored by homeowners and landscape designers for its showy flowers, hardiness and ability to spread. There are now over 40,000 registered cultivars, many of which likely are or have the potential to become invasive and should be watched. For example, yellow daylily (H. lilioasphodelus), has also been identified as invasive in scattered locations in the eastern U.S. Daylily buds and flowers are edible and have a sweet-spicy or peppery flavor.

Distribution and Habitat
Common daylily occurs in every state in the eastern U.S. and in scattered locations west to Oregon. Infestations often occur near old homesites from which they’ve escaped from plantings.

Ecological Threat
Daylilies established in natural areas pose a threat to native plants in field, meadows, floodplains, moist woods and forest edges. Once established, daylily multiplies and spreads to form dense patches that displace native plants. The thick tubers make it a challenge to control.

Description and Biology

• Plant: bulbous perennial, 2-4 ft. tall with round stems.
• Leaves: long, linear, strap-like, bright-green, 1-3 ft. (0.3-1 m) long and curve toward the ground.
• Flowers, fruits and seeds: flowers are large, showy, orange, usually with some striping; occur in clusters of 5-9 at the tip of the stalk; flowers in a cluster open one at a time, each for one day only; summer.
• Spreads: by growth from thick, tuberous roots from which new plants are produced; seed; people tossing away whole pulled plants and by farm equipment or other machinery in fields.
• Look-alikes: native lilies like Canada lily (Lilium canadense), wood lily (Lilium philadelphicum) and Turk’s cap lily (Lilium superbum), and non-native lilyturf (Liriope spicata).

Prevention and Control
Do not plant daylilies known to have weedy habits. Plants can be dug up using a shovel to loosen the soil so that the entire root system with tubers can be removed. Otherwise, re-sprouting will likely occur. Herbicides like glyphosate with systemic action are also effective (see Control Options).

Native Alternatives
Canada lily (Lilium canadense), wood lily (Lilium philadelphicum), Turk’s cap lily (Lilium superbum), three-lobed coneflower (Rudbeckia triloba), and Ox-eye sunflower (Heliopsis helianthoides).