Daylily Diseases and Pests

Daylily ~ Hemerocallis

Daylilies are quite resistant to disease and insects and therefore are one of the most dependable perennials around. They can be affected by some diseases and pests, though, and the more daylilies you collect from outside sources, the greater the chances are of a being presented with disease or a specific pest.


Good growing conditions can minimize potential problems. Keeping your daylilies well watered, fertilized, and weeded will benefit and help strengthen the plants to help to give them the "upper hand" to combat disease or insects.


Daylily Diseases

Crown Rot

Crown rot is most commonly found in warm weather areas during periods of hot, wet weather in poorly draining soils. Once infected, the entire daylily plant will turn yellow, indicating that the rot has probably invaded the crown.


Daylily Rust

Caused by a fungus, daylily rust is indicated by a yellow or orange powdery substance that comes off a daylily when touched. Daylily rust is a relatively new disease in North America, and there is still much to be learned about it. Because daylily rust cannot survive the winter in areas north of Georgia, it is really only a persistent problem for southern gardeners.

Daylily Pests


Aphids can damage the starting growth of daylilies in the spring. This can cause the foliage to yellow. Aphids can also feed on blooms and buds causing warty protuberances and malformed flowers.


Slugs and Snails

Slugs and snails can damage tender early growth of daylilies. They make ragged notches along the edges of the leaves and sometimes through the center. If badly infested, slugs and snails may attack buds and flowers.


Spider Mites

Spider mites feed by piercing the daylily leaves and cause yellowing (and sometimes reddish brown) spots on foliage. If heavily infested, daylily growth can be stunted.



Thrips feed on daylily stems and flower buds. Flower stems may become bent and twisted and the feeding areas are often rough and brown. Few or no flowers develop on heavily infested plants.



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