Web Site Fully Updated for Spring 2024 Data!

The Austin Daylily Rust Study / Trial has gathered spring 2024 data.

There are now 3 pages of cultivars selected from the over 2800 in the database. These pages highlight cultivars appearing to have total, high and moderate rust resistance. The first page Cultivars with no rust ever observed in the Austin Study are daylilies which appear to have total resistance to rust. The second page Highly Resistant Cultivars in the Austin Study are daylilies in the Austin Study that show promise for high rust resistance. The third page Moderately Resistant Cultivars in the Austin Study are daylilies in the Austin Study that show promise for moderate rust resistance. All three of these pages have photos of the cultivars. By clicking on the cultivars photo, a full screen gallery of photos for that cultivar now pops up.

There is more general information about what we learned about daylily rust in 2023 here. And of course all the data from 2023 is in the database which can be searched here.A word document summary with ranked scores of the daylilies studied in 2023 can be downloaded from here.

There is more general information about what we learned about daylily rust in 2022 here. And of course all the data from 2022 is in the database which can be searched here.A word document summary with ranked scores of the daylilies studied in 2022 can be downloaded from here.

There is more general information about what we learned about daylily rust in 2021 here. A word document summary with ranked scores of the daylilies studied in 2021 can be downloaded from here.

What is Daylily Rust?

Daylily rust is caused by the fungus Puccinia hemerocallidis. It is not a new disease of daylilies, having been reported previously from China, Taiwan, Korea, Japan and Russia (Sakhalin, Kuriles and Siberia). It only affects daylilies and it's alternate host plant Patrinia. It will NOT spread to other plants in your garden. It will however quickly spread through susceptible daylilies when conditions are optimal. Optimal conditions are mild temperatures from 60 - 90 degrees F, and high humidity or rainfall.

Daylily rust is a significant problem in USDA hardiness zones 8 and above, as the rust is NOT killed by the usually milder winters. In colder zones, winter freezes usually kill the rust that was brought in on plants grown in the south. All the states bordering the gulf coast are especially affected by it, due to the high humidity and substantial rainfall during spring and fall when temperatures are ideal for it to spread via spores. Coastal areas of California can also suffer from Daylily rust, especially if overhead watering is used.

A little history of daylily rust

Daylily Rust first entered the U.S. in the early 2000's. A number of studies were conducted to determine if some cultivars were more resistant than others. It was discovered that some cultivars show high resistance to rust and others moderate resistance and some no resistance. Daylily rust resistance is probably based upon some as yet unknown genetic traits. Hybridizers have noticed that certain cultivars seem to pass along their resistance to their children.

For more information about daylily rust. Click here to visit a website that has detailed information about daylily rusts life cycle and more, with lots of photos and animations.

What to do about it?

Based upon the published research on daylily rust, there is a very wide range of suseptibility to rust in both the species and hybridized cultivars. Some cultivars show near immunity while others are very highly susceptible. The author has found that alternating highly resistant cultivars with moderately susceptible cultivars, and removing any highly susceptible cultivars, drastically reduces the chance of having your plants look terrible. The photos below show the difference. If you just want a care free daylily bed choose only highly resistant cultivars.

This site was created to help you choose rust resistant Daylily cultivars.

There are four ways to deal with Daylily Rust

• Move North!
• Ignore it!
• Constantly spray fungicides to supress it!
• Select Rust Resistant Cultivars!

How to find Rust Resistant Daylilies?

There are two ways to find rust resistant daylilies on this site. The first is the search page, clicking Search on the menu will take you there. The second are 3 pages containing lists of daylilies which have excellent rust scores located here and here and here.

Whats in The Daylily Rust Database?

The Daylily Rust Database contains the data from all the studies conducted to date.

A new study called the Austin Study was started in late 2020. The database contains all of its data. You can learn more about the Austin study here. All future data from the Austin study will be added to this database.

Some daylily hybridizers now actively select for rust. They discard any seedlings showing rust susceptibility. Cultivars from hybridizers with a rigorous methodology for selecting and scoring their cultivars have been added to the database.