I had iris and daylilies growing in one border, but this year the daylilies are not blooming. Why?
Answer: Irises and daylilies are both stunning perennials with colorful, striking flowers that fill our garden with beauty and intrigue. It can be frustrating when our plants are not able to grant us the gift of a beautiful and full bloom.
Every plant has its own unique needs and challenges. Some may fail due to maintenance/climate issues; bad soil, inefficient lighting and/or damage through pests and diseases. Some may also fail because of overcrowding.
With irises and daylilies sharing the same border, they could be competing for space, ultimately thronging each other out, draining one another of vital nutrients and resulting in insufficient growth. To help ensure the success of your daylilies’ blooms, make sure to give your plants enough space—roughly 18 to 24 inches apart from each other.
For your existing daylilies, try digging up the clumps and thinning them out by removing sections and replanting only the smaller pieces—keeping in mind how much space is in between them. Do the same with your irises. Daylilies can be divided in the spring, just as they start to grow, or in the fall, after they've bloomed (or should have bloomed). The divisions may bloom sparsely their first year, but don't worry. Rhizomatous irises (bearded, Siberian and Japanese) should be divided from midsummer to early autumn. You should divide these plants every three to five years.
After thinning your clumps and properly spacing your plants and you find that you are still have problems the following blooming season, examine your plants for any signs of damage—whether the coloring is off, leaves are wilting, soil is too dry or too wet and/or if there is any evidence of intruding pests.
Image: 'Rocket City' daylily by Epibase
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