Daylily Culture

Daylilies are one of the hardiest perennials on the market.  Little truly bothers them and they can exist with little care, however; they can be much healthier, more floriferous and more pest resistant with a few extra steps.

Planting in full sun will give you the best results.  We don't recommend planting in anything less than 1/2 shade or quantity of bloom will suffer and the bloom scapes will lean toward the sun.

The soil should be average garden soil amended with compost, humus, leaf mould or other organic matter.  Avoid fresh manure as it can burn your plants.  Use extra organic matter to solve clay or sandy soil conditions.  The higher quality your soil is, the better performance your daylilies will give.  More organic matter = less need for fertilization.

We mulch our daylilies for weed prevention and soil moisture retention.  We use bark mulch with the caution that it should be pulled back from the crown of the plants to help avoid crown rot, especially in new plantings and seedlings.  Organic mulches will break down and contribute to the organic matter in the soil.  Fresh mulch can steal nitrogen from the plants so some extra fertilizer could be indicated.
We water thoroughly our new arrivals just after planting, then we give them a week off of watering.  We feel this helps reduce the possibility of crown rot and infections.  Once established, daylilies only NEED to be watered during periods of drought; however, they will perform MUCH better if watered regularly.  Poor watering can result in low bud count and less-vivid coloration on the flowers.  Some older dark purple and red cultivars can waterspot with overhead watering, so soaker or ground-level watering is recommended with these cultivars.

Here's a link to a the AHS diagram of the parts of a daylily plant.

When planting your new daylily, dig a hole at least 18" wide and 12" deep, mix in lots of organic matter (some people also mix in alfalfa pellets, bone meal or slow-release fertilizer), and then make a hole in the middle of where you want the daylily to be.  Mound up dirt in the middle of the hole to support your plant (you don't want it to sink too low when the dirt settles).  Place your new daylily on top of the mound with the roots spread down the mound toward the bottom of the hole.  Make sure the crown of your daylily is level with the final surface of the soil (not too deep!!).  Backfill your hole, gently tamp the soil, mulch and water well.  Remember not to let the mulch touch the sides of your daylily.  That's about it for planting!

Click here for pictures showing this planting technique.

There exists lots of controversy about fertilizers.  The organic gardeners don't like any man-made chemical fertilizers and use good soil health (lots of organic matter) as the key to their success.  We are not adverse to using a slow-release fertilizer (like Osmocote) in the spring and then again during bloom.  Be very careful with fertilizers during the very hot parts of the summer, they can burn or kill your plants.

There exist few pests to daylilies.  The most noticeable was the arrival of daylily rust from outside the U.S.  It has swept the southern states and can be either accepted or fought with expensive fungicides.  It remains to be seen if the current thought that daylily rust cannot survive in colder climates.  We are currently rust free.  We do buy from Florida and southern gardeners however we do spray new arrivals with fungicide.

Here's a link to the AHS website about daylily rust.

Crown-rot is another possible problem with daylilies.  In our opinion there is no treatment.  Some people dig them up and soak them in 10% bleach, dry and then replant.  Some plants that we have seen succumb to rot will have small bits of the crown survive and send up new foliage from latent buds.  Here in our zone 7 garden with over 1,000 daylilies, we lose less than 10 plants a year to crown rot.  It is mostly seen on new plantings (especially those planted in the summer) and during a wet spring.

Spring Sickness does happen here in our zone 7 garden.  Nobody is quite sure how it happens, but I think we agree that it is not fatal to the plant.  Leaves appear twisted and stunted with jagged/ragged looking discolored edges.  Our advice is to wait it out, the plant will recover but may be set back a little.

Leaf Streak is a common fungal disease that causes the tissue to turn yellow then die (once dead it is brown).  Thrip damage can be a point of entry for the disease.  Early detection and fungicides can help.  Wet spring season can cause an increase in leaf streak.  Leaf streak is unsightly but not fatal.

Other daylily pests are aphids, thrips, slugs and snails.  All can be controlled with organic or synthetic insecticides.  Some people prefer using ladybugs as predators.  Slugs and snails can be baited or trapped and are rarely a big pest of daylilies.

Daylily Doyle Pierce