To extend their marketing and sales windows, many growers seek daylily cultivars that have long blooming periods and reblooming characteristics. Nearly every grower is familiar with or already produces ‘Stella D’Oro’, which is widely recognized as an easy-to-grow and reliable reblooming daylily. For growers looking for these surefire characteristics in a red-blooming cultivar, let me introduce to you ‘Ruby Stella’, the sister of ‘Stella D’Oro’.
Stamina and reliability are two words to describe ‘Ruby Stella’, as it consistently produces flowers from June through the first frost without the need for deadheading. The slightly fragrant, dark wine–red, 3-inch blooms with yellow throats are held neatly above its compact 12- to 14-inch foliage. When in bloom, this mid-size dwarf clumper reaches 16-20 inches tall.
‘Ruby Stella’ prefers locations with full sun to partial shade and is tolerant of a wide variety of growing conditions. Once established, it can withstand heat and drought better than most commonly grown perennials. Conversely, it can tolerate occasionally wet sites but does not perform well in consistently waterlogged soils. These attributes give hemerocallis the reputation for being one of the toughest, most adaptable perennials used in the landscape.
Daylilies perform well through-out USDA Hardiness Zones 3 to 10 and AHS Heat Zones 12 to 1. They’re also versatile, commonly used as groundcovers, border plantings, mass plantings, for naturalizing and in patio containers. Additionally, hemerocallis is rabbit and deer resistant and often attracts hummingbirds and butterflies to the garden.
Hemerocallis ‘Ruby Stella’ is vegetatively propagated by division by licensed propagators. Unlicensed propagation of this cultivar is prohibited because a plant patent is being sought (PPAF — Plant Patent Applied For).
‘Ruby Stella’ is primarily available to commercial growers as bareroot divisions, but in some cases, it can be acquired as rooted liners. Because of economics, it is used mostly in 1-gallon or larger sized pots, although it can be produced successfully for some markets in smaller containers, such as quarts or 5-inch pots. Daylilies are easy to produce; the following production guidelines will improve crop uniformity and performance.
Bareroot divisions or large plugs of ‘Ruby Stella’ perform best when planted in a well-drained potting medium. Many growers use mixes containing various components including bark, peat moss, coir, sand or perlite. When planting from bareroot divisions, spread the roots over a central cone of growing mix in the center of the pot. Fill the pot, covering the crown with about an inch of growing medium. Water them in thoroughly after potting and place them in the production area.
Fertilization is generally not necessary during the first few weeks of production. Once established and actively growing, ‘Ruby Stella’ is a moderate feeder requiring a controlled-release fertilizer incorporated at a rate equivalent to 1 pound of elemental nitrogen per yard of growing medium or 75- to 125-ppm nitrate delivered under a constant liquid fertilizer program or 200-250 ppm as needed. The pH of the media should be maintained between 6.2-6.7. Avoid overfertilization, as it may lead to soft, spindly growth.
Until daylilies are established, keep the rooting medium evenly moist. Once established, water them thoroughly when irrigation is required, and allow the substrate to dry slightly between waterings. Routine watering during bud development will improve the quality of the flowers.
With its compact habit, ‘Ruby Stella’ usually does not require height control strategies, but under certain growing conditions or at high plant densities, height management might be necessary. Provide adequate spacing between the plants to reduce plant stretch caused by competition. Spray applications of daminozide at 3,000 ppm or the tank mix of daminozide at 2,000 ppm plus uniconazole at 3 ppm will effectively control elongation. Foliar applications usually require two to three sprays at seven-day intervals to provide adequate height control. Begin making foliar applications when the plants reach 3-6 inches tall. One-time drench applications of ancymidol at 6 ppm, paclobutrazol at 6 ppm or uniconazole at 1 ppm are also highly effective at reducing plant height. Drench applications should be applied at approximately the same time foliar applications are typically made.
‘Ruby Stella’ is a “dormant” variety that loses its foliage after frost and remains leafless throughout the winter months in most regions of the country. As fall approaches, withhold nutrients or decrease fertilization to allow the plants to “shut down” as they prepare for their winter dormancy. In the late fall after the first hard frost, trim the plants back to 2 inches above the top of the container. Once they are trimmed, group the pots together inside a coldframe, greenhouse or outdoor production bed. In colder zones, cover them with a protective frost fabric during the winter months.
Pests and Diseases
Daylily ‘Ruby Stella’ is not susceptible to many insect pests. Aphids, spider mites and thrips are the most prevalent insects. Preventive programs for spider mites and thrips (beginning just prior to flowering) are often beneficial and can keep these pests from causing injury to the foliage and flowers.
There are only a couple of diseases associated with the production of daylilies. A crown rot sometimes occurs shortly after overwintering; this tends to be observed on evergreen cultivars. Although seldom a concern, inadequate aeration during cool, wet weather may lead to soil-borne fungal infections from Fusarium or Rhizoctonia. Foliar diseases with symptoms of leaf spots and leaf streak — caused by the fungal pathogens Aureobasidium microstictum, Alternaria alternate and various Fusarium species — are commonly observed.
Daylily rust caused by the fungal pathogen Puccinia hemerocallidis may become prevalent, particularly in the southern United States or when starter plants were purchased from outside the country. Daylily rust does not overwinter in the northern parts of the country, so growers carrying over hemerocallis in these regions are less susceptible to this fungal disease.
Hemerocallis are classified as cold-beneficial plants because flowering is usually more uniform following vernalization. Although they are considered day neutral, growers typically achieve more uniform flowering, more flowers per plant and the best appearance when the plants are grown under long days.
In lieu of this classification, I view them as long-day and high-light-beneficial plants as the flowering improves with both the photoperiod and light levels. However, providing night-interruption lighting is not always effective at promoting flower development since the light intensity during the day is often low. When possible, force them into flower under high light levels and warm temperatures.
There are two common methods growers use to produce flowering daylilies. The first entails planting (usually bareroot) in the early spring and growing them with an average temperature of 60-65° F. At these temperatures, ‘Ruby Stella’ will reach a finished size in six to eight weeks and will be flowering in about 10 weeks. The second strategy entails planting daylilies in the late summer or early fall, overwintering them and forcing them for sales in the late spring or early summer. From my experience, the late-summer plantings always produce a more consistent crop with significantly more flowers compared to hemerocallis planted in the early spring for same year’s sales.
Hemerocallis ‘Ruby Stella’ is primarily available as bareroot divisions and can be obtained from several reputable plant suppliers.