Diseased daylillies - Ask Extension
I have quite a few daylilly plants in my yard that just don’t look healthy. They are light green, twisted leaves, and last fall a majority of the l...
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Diseased daylillies #789339
Asked May 04, 2022, 8:04 PM EDT
I have quite a few daylilly plants in my yard that just don’t look healthy. They are light green, twisted leaves, and last fall a majority of the leaves had some sort of die-off going on. I’ve looked up different possibilities, but thought maybe an expert could tell by my photos here :-). I saw a list of disease resistant varieties, but none of the nurseries seem to carry them. If it is disease, any ideas where I can find the disease resistant cultivars? And if not, should I just dig them up and try something different? Thanks in advance!
Oakland County Michigan
Expert Response
Hello JoAnn,
Your daylilies do seem to be having problems. Are these pictures from this year or from last year when the problem started? If they were from last year, were the flowers affected? How long have you had daylilies in that area? Have you checked for aphids or other insects? Did you rake up all the dead leaves from last year and clean the area of any debris?
Diseases and insects are usually not a serious problem for daylilies. Treatments and good cultural procedures usually are effective. The three common diseases that affect them are leaf scorch, rust, and leaf streak. Of the three, I would suspect leaf streak. However, I can't be sure since some of the markings I see might be caused by the glare of the sun. The following article from the University of Illinois Extension offers some helpful information about these diseases.
http://hyg.ipm.illinois.edu/pastpest/200711c.html
A much more serious problem is Root-knot nematodes.
They feed on the roots of plants. The feeding process damages the plant's root system and reduces the plant's ability to absorb water and nutrients. If you check out the roots of some of the affected plants, you would see knot-like bumps on the roots. You could also send a whole plant sample to MSU for identification;
Plant & Pest Diagnostics (msu.edu)
The following article from Clemson University Extension gives more information about nematodes and also about insect problems.
https://hgic.clemson.edu/factsheet/daylily-diseases-insect-pests/
Finally, there are some disease resistant cultivars: Chicago Apache, Carolyn Criswell, Mardi Gras Parade and Buttered Popcorn, to name a few. Some of the large greenhouses in Oakland County may carry them. More likely is that you will have to purchase these online.
If you have any further questions or need clarification, don't hesitate to contact us again.
Your daylilies do seem to be having problems. Are these pictures from this year or from last year when the problem started? If they were from last year, were the flowers affected? How long have you had daylilies in that area? Have you checked for aphids or other insects? Did you rake up all the dead leaves from last year and clean the area of any debris?
Diseases and insects are usually not a serious problem for daylilies. Treatments and good cultural procedures usually are effective. The three common diseases that affect them are leaf scorch, rust, and leaf streak. Of the three, I would suspect leaf streak. However, I can't be sure since some of the markings I see might be caused by the glare of the sun. The following article from the University of Illinois Extension offers some helpful information about these diseases.
http://hyg.ipm.illinois.edu/pastpest/200711c.html
A much more serious problem is Root-knot nematodes.
They feed on the roots of plants. The feeding process damages the plant's root system and reduces the plant's ability to absorb water and nutrients. If you check out the roots of some of the affected plants, you would see knot-like bumps on the roots. You could also send a whole plant sample to MSU for identification;
Plant & Pest Diagnostics (msu.edu)
The following article from Clemson University Extension gives more information about nematodes and also about insect problems.
https://hgic.clemson.edu/factsheet/daylily-diseases-insect-pests/
Finally, there are some disease resistant cultivars: Chicago Apache, Carolyn Criswell, Mardi Gras Parade and Buttered Popcorn, to name a few. Some of the large greenhouses in Oakland County may carry them. More likely is that you will have to purchase these online.
If you have any further questions or need clarification, don't hesitate to contact us again.
