One year, a couple of my daylilies did not bloom as expected. I found his quite puzzling as they had bloomed very nicely in previous years. I had done everything I thought was important for good daylily blooms; fertilizer, plenty of water, lots of stable sweepings as mulch. The plants looked good, the foliage was nice and green, just no blooms. I was stumped.
In the fall, I dug them up in order to move them. Much to my surprise, I found that the daylilies had two crowns, one about 1.5 inches above the other (the crown is where the roots are attached to the plant). I noticed that the lower crowns were actually about 3 inches below the level of the soil. The daylilies were planted way too deep and had stopped their normal growth cycle to re-establish a new set of roots at the proper soil depth. That's why I didn't get any blooms. This really shows that proper planting depth is very important.
Note: Actually, I had not planted the daylilies too deep. They were planted at the proper depth, but repeated applications of mulch right up to the plant added the additional soil depth as it decomposed.
More common reasons for failure to bloom:
- Daylilies need lots of sun to perform well. I daylilies that don't get enough sun they may have only a few small blooms or they may not bloom at all. Sometimes daylilies which previously bloomed well may start performing poorly and may even stop blooming all together. This can be caused by nearby trees that have grown and are now providing too much shade.
- Many daylilies need to be divided from time to time to perform at their best. When a daylily forms a large clump the plants can get very crowded. Usually this results in smaller and fewer blooms but doesn't cause the blooming to stop.
- Dividing during (or right before) a hot summer can cause problems for daylilies. If the plant's roots haven't had a chance to get established the plant will suffer. The plants usually survive but at the end of the summer they can be quite small - too small to bloom the following year.
- Dividing too late in the fall can result in the daylily roots not being established before the ground freezes. This can damage the plant to where it may take a couple more years to reach blooming size. It is recommended to not divide daylilies less than 6-8 weeks before the first frost date.
- Daylilies may not be well suited for the local climate. Dormant varieties in the south and tender varieties in the north are examples and either case may cause the plants not to bloom at all. Dormant plants in the south continue to grow after the time they should be going dormant. This uses up the plant's root reserves and results in a greatly weakened plant. Evergreen varieties in the north will often be damaged by the freezing temperatures. The plant may survive but by the time it recovers it's too late to bloom.
- Agressive root systems from nearby trees and shrubs are another common cause for daylilies not to bloom. The masses of roots will take all the nutrients and moisture from the soil. In some cases, a large tree can remove all the water from the soil surrounding its roots in just a short time robbing the daylilies of needed water.
- Something that has just recently started affecting southern daylilies is daylily rust. Some daylilies are hardly affected at all by rust while others can get severly infected if not treated. Even severe cases of rust usually don't kill a daylily but the worst cases can weaken the plants to the point where they may not bloom. More information can be found by clicking here. Rust does not survive the winter where there is a lengthy period of freezing temperatures so it has not been a major problem in the north.