There are more than 40,000 different registered Hemerocallis (daylily) cultivars suitable for landscape gardens. The dilemma for backyard gardeners as well as landscape contractors is choosing the best cultivars for particular situations.
To make choosing easier, consider selecting All–American Daylilies for projects. Evaluated and picked from test plots that range from United States Department of Agriculture (USDA) plant hardiness zone 10 in Florida and California to Zone 2 in Alberta, Canada, All–American Daylily cultivars sell nationwide in blue pots that display the All–American Daylily logo.
The All-American Daylily Selection Council (AADSC), organized in 1989 to evaluate daylilies for their overall performance, administers daylily test sites throughout North America. AADSC members carry out rigorous evaluations of test daylily cultivars using 52 performance characteristics.
The First All–American Daylily
The first daylily to receive the All–American Daylily designation in 1994 was "Black Eyed Stella." Hybridized and registered in 1989 by Jack Roberson, it improved upon 'Stella de Oro." American Daylily & Perennials, Inc., of Grain Valley, Missouri introduced "Black Eyed Stella" in 1994.
"Black Eyed Stella" displays its nearly 3 1/2-inch red–eyed golden–yellow blooms 100 to 297 days per year in nine United States Department of Agriculture (USDA) growing zones. Blooms are borne on slender 12 to 22 inch– tall scapes accompanied by dense, finely textured dark green 10 to 18 inch – tall evergreen foliage. With good rust resistance and heat tolerance, this daylily is an improved alternative to "Stella de Oro" for Pacific and Gulf Coast landscapes.
Primary Characteristics Evaluated by AADSC
Length of bloom for specific growing zones should be about the same as for all garden perennials in that zone. Average daylilies bloom for about two to three weeks. All American Daylilies will bloom for 60– to 90% of a specific zone's overall bloom period for perennials.
Foliage performance is the second strongest evaluation characteristic. Will foliage still make an attractive ground cover between bloom periods? The AADSC looks for high-quality foliage color and density, the difference between a beautifully manicured and a shabby–looking landscape garden. According to the AADSC, top-notch daylilies provide 18 weeks of super-looking foliage, fewer weeks in the north, more in the south.
The AADSC Simple Guide to Choosing "Drop Dead" Daylilies
- Check buds - Pick plants that show at least 15-20 buds or scars indicating previous bud attachment on the scape. Signs of past or present strong scape making are also good guides.
- Check foliage color- Look for rich green or blue-green foliage. Intense foliage color indicates that plants continue to be garden assets with or without bloom.
- Check foliage density - Look straight down into the pot. Choose the daylily whose foliage covers the fill material below. The greater the foliage density, the earlier the planting achieves a finished look.
- Check existing bloom – Pick out daylilies in afternoons on hot days to avoid those that are not sun-fast. In hot sunny conditions, some light–colored blossoms "bleach out" by midmorning, while darker colored blossoms may “slick,” i.e. surface cells that hold pigment change color and often their contents drip off the flower. Usually, planting dark purples and reds - prone to color loss - in shady areas minimize color change and bloom drop.
- Check spent bloom - Look for “self-cleaning” daylilies. The best daylilies roll spent flowers into little cigarette-shapes. Usually, self-cleaners lose these unassisted in two days. Some daylilies retain these spents for a week. Tap spents with your finger on potential purchases. They drop off easily on winners.
- Check scape and foliage heights - A scape that carries blooms at least an inch or two above the general mass of the foliage is the best choice. Otherwise, foliage hides the blooms.
Georgene A. Bramlage - Suite 101 Landscaping Feature Writer and Topic Editor Free-lance Garden and Landscape Writer and Consultant
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