The daylily, Hemerocallis, is valued by gardeners for its robust nature and ability to thrive in varied conditions. These resilient perennials can often withstand drought, yet their tender buds and nutrient-rich roots make them a popular target for animal pests. Identifying the specific culprit behind the damage is the first step toward protecting the plant’s foliage and blooms. Damage can range from small blemishes to the complete destruction of the root system, requiring different control strategies.
Mammalian Pests That Consume Foliage and Flowers
The most visible damage to daylilies is caused by larger herbivores that feed above ground, primarily deer and rabbits. These animals leave distinctly different feeding patterns that help pinpoint the pest responsible. Deer typically target flower buds and upper foliage, often browsing at heights between one and six feet. Since deer lack upper incisor teeth, their feeding results in a torn and ragged appearance on the leaves and stems, frequently leaving behind splintered stem breaks.
Rabbits, conversely, feed close to the ground, usually targeting young shoots and stems no more than six inches high. Their sharp incisors allow them to make a clean, precise cut on the plant material. Rabbit damage often looks as though the stem has been neatly clipped at a 45-degree angle. Both animals are primarily nocturnal feeders, so damage is often discovered the following morning.
Subterranean Pests That Target Roots and Tubers
Some of the most destructive pests operate below the soil line, causing entire daylily clumps to suddenly wilt and die. Voles are small rodents that tunnel near the soil surface, creating irregular surface runways. They consume the fleshy crown and roots of the daylily, often girdling the plant at its base. A plant damaged by voles can be easily pulled out of the ground because the root mass has been eaten away.
Pocket gophers are another subterranean threat, characterized by mounds of excavated dirt near the plant site. Gophers will pull an entire plant into their tunnel system, causing the daylily to vanish overnight. Diagnosing this damage requires examining the planting hole, which reveals an underground tunnel entrance rather than just gnawed roots. These pests cause total plant loss rather than merely cosmetic injury.
Smallest Pests: Slugs, Snails, and Insects
A variety of invertebrates can significantly reduce the aesthetic value and health of daylilies. Slugs and snails are mollusks that leave behind a characteristic silvery slime trail as they move and feed at night. Their feeding creates irregular holes in the middle of leaves and ragged notches along the edges, particularly on tender spring growth. Reducing ground moisture and removing debris helps limit their activity.
Minute insects, such as aphids and thrips, primarily target new growth and flower buds. Aphids are soft-bodied insects that cluster on stems and buds, sucking plant sap and causing deformed leaves. They excrete honeydew, which can lead to the growth of black sooty mold on the foliage. Thrips, which are barely visible, cause damage that appears as yellowish speckles or streaking on the petals, resulting in distorted or discolored flowers.
Effective Deterrence and Protection Methods
Protecting daylilies requires employing measures tailored to the identified pest, starting with physical barriers for large mammals. Tall, sturdy fencing, at least eight feet high, is the most reliable method for deterring deer. For rabbits, a low barrier of chicken wire or hardware cloth surrounding the bed, extending at least two feet high and buried a few inches into the soil, provides effective protection. Scent and taste repellents, often containing putrescent egg solids, can be sprayed directly onto foliage to discourage deer browsing.
Controlling subterranean pests necessitates protecting the root ball at the time of planting. New daylilies should be planted inside a wire basket made of galvanized hardware cloth with a small mesh size. The rim of this basket should protrude an inch or two above the soil line to prevent voles and gophers from entering from the surface. Applying castor oil-based granular repellents into active vole runs can also encourage the rodents to relocate their tunnels.
Managing invertebrate pests involves cultural practices and targeted treatments. Slugs and snails can be managed by removing their daytime hiding spots, such as excess mulch or large stones, to reduce moisture. Iron phosphate-based granular baits offer a non-toxic method of control that is safe for surrounding wildlife. For small insect infestations, a strong jet of water can dislodge aphids, while insecticidal soap or dusting with diatomaceous earth can be used on affected foliage to manage thrips and mites.