The daylily, Hemerocallis, is a resilient perennial valued for its striking, trumpet-shaped blooms and adaptability. While each individual flower lasts only a single day, the plant produces a succession of new blooms over many weeks. Maximizing and extending this flowering period throughout the summer requires understanding the plant’s genetics and applying specific maintenance practices.
Selecting Varieties for Recurrent Blooming
Achieving a summer-long display begins with choosing the right cultivars, as not all daylilies are genetically programmed to rebloom. Many older varieties, known as diploids, typically offer a single, concentrated bloom period of three to four weeks before the season concludes. These single-season bloomers enter a dormant state that prevents a continuous display.
The key to extended flowering is selecting a cultivar designated as a “recurrent bloomer” or “ever-blooming.” These varieties are often tetraploids, possessing double the number of chromosomes compared to diploids. This genetic difference results in larger flowers, sturdier stems, and a greater tendency toward repeat flowering cycles throughout the summer and into the fall. Varieties labeled “extended bloom” or “rebloom” indicate a predisposition to send up multiple flower stalks, or scapes, after the initial flush of flowers has finished.
The Essential Practice of Deadheading
Deadheading is the most immediate action for encouraging a daylily to produce a second or third wave of flowers. The plant’s reproductive instinct is to set seed after flowering, which consumes energy that could otherwise be directed toward new growth and subsequent blooms. Removing the spent flowers manually interrupts this energy-intensive seed production cycle.
This practice involves a two-part process performed regularly, ideally every few days during the peak season. First, pinch or snap off the individual spent flowers, ensuring the swollen base—the ovary containing the potential seed pod—is removed. This prevents seed pod formation, which is the primary drain on the plant’s resources.
Second, once all the individual flower buds on a single stalk (scape) have opened and faded, the entire leafless scape should be cut back completely. Use sharp shears to sever the stem close to the ground, just above the foliage line. Removing the entire finished scape signals that the reproductive cycle is incomplete, prompting the plant to develop new scapes for a repeat performance. Consistent removal of both spent blooms and finished scapes is the most effective way to sustain flowering.
Sustained Support: Watering and Fertilizing
Continuous flowering places a high energy demand on the plant, requiring support through consistent hydration and nutrient delivery. Although established daylilies tolerate dry conditions, water stress quickly halts the development of new flower buds and prematurely ends the summer bloom. Providing deep, consistent watering is required, particularly during dry spells when the plant is actively pushing out new scapes.
When watering, focus on soaking the soil deeply around the root zone rather than just wetting the foliage. This encourages a robust, deep root system capable of supporting the energy expenditure of repeat blooming.
Fertilization should be approached with caution, as daylilies are not heavy feeders, but a light application supports the sustained energy demands of rebloomers. Avoid high-nitrogen fertilizers after initial spring growth, as these promote excessive leafy growth at the expense of flower production. Instead, apply a low-nitrogen, high-phosphorus formula (e.g., 5-10-10 ratio) around mid-summer, immediately after the first major flush of blooms. The higher phosphorus content supports bud formation and flower development, fueling the next round of recurrent scapes.
Maintaining Vigor Through Division
Daylilies grow from a crown and gradually expand into dense clumps, leading to overcrowding. This condition, sometimes called the “clump-out” effect, results in a decline in the size and number of flowers. The dense mass of roots and foliage competes heavily for nutrients and moisture, reducing the plant’s vigor and capacity to produce abundant flowers.
To rejuvenate the plant and restore maximum bloom potential, division is necessary, typically every three to five years. The best times for this maintenance are in early spring as new growth emerges or in late summer to early fall after the blooming season has concluded. Dividing at these times allows the separated sections, or fans, to establish new roots before environmental stress.
To divide the clump, carefully lift the entire root mass from the soil using a garden fork. The clump is then separated into smaller sections, ensuring each new piece contains at least one fan of leaves and a healthy portion of the roots. Replanting these divisions with adequate space improves air circulation and nutrient availability, ensuring the plant retains the energy reserves needed for a robust display in subsequent summers.