What to do with daylilies that dont bloom?

Most daylilies (Hemerocallis cvs) bloom year after year without your having to do much of anything: they are very reliable and very permanent plants. But some varieties, even though they are treated the same way and grow under the same conditions, bloom less after they have been in the ground 5 or 6 years. They may stop blooming entirely. The very popular ‘Stella de Oro’ daylily – the mostly widely sold daylily in the world – belongs to this category. After a number of years, it just doesn’t bloom the way it used to. What’s wrong?

Competing With Itself

If a daylily is no longer blooming well yet others around it are still going strong, the problem most likely has nothing to do with fertilizing, watering, exposure, or other cultural factors, but rather results from overcrowding. And not overcrowding caused by other plants (most daylilies can hold their own in that department!), but with itself. It has produced so many offshoots that there is now a profusion of plants that share the same space, each competing with its neighbors for light and minerals. This intense competition reduces or eliminates flowering. It’s as simple as that.

Time to Divide

And the solution is just as simple: divide the plant. Maybe not when you notice the problem, in midsummer, but either in the fall (at least one month before the first frost) or the spring, when new shoots start to appear. That’s because daylilies respond better to division when they are more or less dormant. (And in the fall, even though they still have leaves, the average daylily is pretty much asleep.)

That said, you can divide a daylily in summer if you really want to, but it’s more of a shock to the plant and it’s therefore extra important to water regularly to help it make a complete recovery.

Daylily Division

Dividing a daylily is pretty basic.

Start by just digging up the entire plant with a spade, taking the biggest root ball possible. If you do it late in the season (late August, September), you can shear the foliage to 8 inches (20 cm) high before starting so you can better see what you’re doing… if you want to (shearing is not absolutely necessary).

Slice through the plant with the spade to cut it into 2, 3, 4 or more sections. Each section must have at least one  healthy fan; preferably 3 or more. Now replant each section without burying the crown (the junction between the roots and the stem)… in other words, plant it with its leaves at the same level as they were before the division.

After the division, water well and apply a mulch. The plant will need additional watering in case of drought until it is well established and that can take a full year.

If you end up with too many plants, no problem: they make great gifts for friends and neighbors!

Once replanted, your divided daylily will likely flower at least modestly its first season and heavily from then on. And after 5 or 6 years, since it is one of those daylilies, it will be time to repeat the process!

Daylilies (Hemerocallis spp.) are generally hardy in U.S. Department of Agriculture plant hardiness zones 3 through 10. Depending on climate zone and species or variety, the plants can be deciduous, semievergreen or evergreen. The showy, trumpet-shaped flowers bloom in all colors except true blue and are available in single or double forms. Some daylilies also rebloom over the course of the growing season. Those that don't bloom may be affected by disease or pests.

Hard Buds

1. Daylily "buds" that feel hard to the touch may not be buds, but rather seedpods, which form on both once-blooming and reblooming varieties. The differences between true flower buds and seedheads are easy to recognize. True flower buds are elongated, with soft creases running the length of the bud. Seedpods form right after flowering is finished. They are generally light green, rounded and unyielding to the touch. Remove the seedpods to stimulate flower production in reblooming varieties and strengthen once-blooming plants for the next year's bloom cycle.

Tarnished Plant Bugs

1. Tarnished plant bugs (Lygus lineolaris) are small, brown insects about 1/4 inch in length as adults. Yellow-brown in color, the bugs have triangle markings on their backs. Immature tarnished plant bugs bear a superficial resemblance to aphids. Like aphids, the tarnished bugs harm plants such as daylilies by inserting sharp beaks into various parts, including flower buds, and sucking out juices. This results in daylily buds that do not open or produce misshapen flowers. Tarnished plant bugs are worst when conditions are dry.

Bug Prevention

1. Tarnished plant bugs overwinter in plant debris left in the garden, so the best way to avoid infestation is to do thorough garden clean-up in the fall. If the bugs are detected during the growing season, remove unopened flower buds and any other affected plant parts. Spray affected daylilies with insecticidal soap, applied according to manufacturer's directions. Insecticidal soap must be reapplied after every rain. The optimal time to spray is early morning.

Other Suspects

1. Some diseases and insects cause deformed buds that shrivel, rot or become dry or hard. Gray mold (Botrytis), a fungal disease prevalent in humid weather and spread by airborne spores, affects ornamentals and edible crops, including daylilies. The affected plant parts sometimes show gray, fuzzy mold. Gall midge (Contarinia quinquenotata) is a tiny fly whose larvae infest daylily buds, resulting in abnormal swelling that makes buds firmer than normal, followed by death. The best treatment option for both botrytis and gall midge is quick removal of affected plant parts. When using clippers, disinfect between cuts with undiluted bleach.

By Meg Schader Updated November 20, 2020

Prolific bloomers in U.S. Department of Agriculture plant hardiness zones 3 through 9, daylilies (Hemerocallis spp.) are known for their large, colorful blossoms. Though each bloom adorns the landscape for just one day, daylilies produce so many, that they may seem like they are constantly in bloom throughout the summer. Unfortunately, daylilies can sometimes disappoint even the greenest thumbs, and veteran gardeners may be left wondering why their daylilies won't bloom. However, daylily bloom problems can often be solved with just one cultural change, and you can usually turn them back to their flowering glory for the next growing season.

If your daylilies are not blooming well this season, one of the most common reasons is that they are not planted at the proper depth, according to Oak Forest Technology Solutions.

To determine if this is the cause of your lack of blooms, dig down around a plant carefully with a clean trowel and verify that the tops of your daylily rhizomes are located just below the soil, about 1 inch. If you regularly add mulch to your garden, your daylilies may now be planted deeper than they were originally, and daylilies that are planted too deeply or buried under too much mulch will not bloom. Dig up the rhizomes and replant, if necessary.

Another frequent problem with daylilies is lack of sufficient sunlight. According to the American Daylily Society, daylilies need full sun – which means six or more hours of sunlight a day. Observe the amount of sunlight your daylilies receive each day, and transplant the rhizomes to a sunnier location, if necessary. Alternatively, prune nearby trees and shrubs to increase sunlight exposure to your daylilies.

South Dakota State University Extension notes that deadheading is essential for encouraging more blooms. Faded flowers that are not removed will put energy into developing fruits and seeds, which will leave less energy for the plant to make more blooms. Deadheading daylilies will significantly impact the number of blooms each plant produces.

Additionally, daylilies typically need dividing every three to seven years to thrive. Divide daylilies that are overcrowded, often displaying an abundance of green growth, but few to no blooms. Dig around each clump with a garden fork and lift the rhizomes from the soil. Cut the rhizomes with a knife so each section has two or three fans of growth, and replant.

Even though the plants need to be split up to thrive in the long run, dividing can set plants back for a season or two. If daylilies experience a hot summer right after being divided in the spring, the plants may not grow big enough to flower. And if daylilies are divided too late in the fall, they may not have time to grow strong roots, which may result in blooming problems until they become established in their new location.

Water daylilies weekly during spring and summer with 1 inch of water. Water with an additional 1/2 to 1 inch of water if your daylilies are competing with nearby shrubs and trees for water. Water in the morning so the foliage can dry out before evening.

Fertilize daylilies yearly in the spring with an all-purpose, balanced fertilizer, such as 12-12-12 or 10-10-10. Sprinkle the fertilizer around the clumps, but do not touch the foliage with it. Use the amount instructed on the label. If your soil is light or sandy, fertilize again in the summer and early fall.

Cut off daylily foliage only after it yellows. If the foliage is still green, your daylilies are still making energy and storing it in their rhizomes for next year's flowers. If you regularly remove the foliage after blooming, in a year or two, your daylilies will not bloom.

Things You Will Need

• Pruning shears

• Garden fork

• Knife

• Fertilizer

• Garden hose

If you fertilize and properly care for your daylilies in all other ways, and they are not blooming, you may be fertilizing them too much. Stop fertilizing or reduce dosage by half to see if that helps.