May 2010

Alcea Spotlight Series By Allen Bush

It's hard to improve on Henry Phillips' praise of hollyhocks in 1824's Flora Historica, where he wrote: "Its noble size, majestic height and splendid flowers could not fail to attract the attention of our earliest collectors of exotic plantsÉ" These collectors probably found them along the Silk Road traveling from Turkey into China. Even now, gardeners can seldom walk through a garden center or look through a perennial catalogue without finding a few hollyhocks. Gardeners have been planting them for a long time. There are Neanderthal remains of hollyhocks, from archaeological excavations in Iraq, dating back more than 60,000 years ago. It wouldn't be unkind to call them old-fashioned; this classic's popularity is undiminished after all this time.

Gardeners like them because they are easy to grow, flower the first season and self-sow around the garden; children can make dolls' skirts out of the cup-shaped blooms from May to October; and growers can easily produce salable plants within 12 weeks.

Jelitto has had a passion for alceas for many years. The 2010 catalog includes a wide selection, from wild species to popular older, double-flowering strains. Breeding on the single-flowering Spotlight series began in 1992; though the task was challenging, General Manager Georg Uebelhart felt that the development of consistent strains in straight colors of Alcea rosea would be worth the effort. The result is consistent single flowers of the darkest black-purple ('Black Knight'), pure white with yellow eye ('Polarstar'), red colors ('Mars Magic') and light yellow ('Sunshine').

The Spotlight series grows nearly 6 feet tall and is a strong, recognizable presence in the cottage garden or at the back of any perennial border in well-drained soils. The series combines magnificently together, in the full sun with echinacea 'Hula Dancer', Eupatorium fistulosum 'Ivory Towers' and helianthus 'Lemon Queen Strain'. The Spotlight series is hardy throughout North America from Zones 3 to 9.

Scheduling
Jelitto's seed technology greatly improves mechanical handling and seed sowing. The alcea Spotlight series can be sown any time and requires four to six weeks for germination. Sow two to three seeds per cell in 72- or 128-cell plug trays, then maintain warm greenhouse temperatures of 68-75¡ F for five days. Germination will be more consistent if exposed to moist, cooler temperatures (33-41¡ F) for two to three weeks after the brief warm period. Allow four to six weeks from germination to transplant in 4- to 5-inch containers; or two plants per gallon size. Plants can be finished in an additional four weeks.

Culture
Traditional perennial growers sow alceas in the late summer in order to vernalize over the winter, either in large plugs or in finished containers. Others prefer a quick crop sown in winter for the spring market. Vernalization is not essential but will improve quality.

Use a well-drained media that won't become overly saturated. The Spotlight series will quickly produce a healthy root system in a bark and perlite mix with pH of 5.8-6.8. Hollyhocks are not heavy feeders, and balanced 150- to 200-ppm nitrogen will promote sufficient growth. Maintain an E.C. of 0.6-0.9. Keep the plugs moist following transplant, but do not overwater.

A constant feed of 50-ppm nitrogen can begin two weeks after germination and can be increased to 75-100 ppm twice a week with an EC of 1.0 in the third week until transplant. Fertilize with a balanced constant feed at 100-150 ppm once a week in the greenhouse with an EC of 1.5. For outdoor production, apply 13-13-13 slow-release fertilizer at a rate of half a teaspoon per quart size or 1 teaspoon per gallon.

Growth Regulation, Disease and Insect Control
Allow the plants to dry out thoroughly between watering to prevent the telltale orange spores of the rust disease Puccinia malvacearum, which can be a foliar nuisance but needn't be a greenhouse problem. Alceas are not prone to root diseases, though anthracnose and cankers have been reported. Slugs and Japanese beetles can skeletonize garden foliage but shouldn't affect plant production. Pay attention to spider mites in the greenhouse. The simplest control for height and for Puccinia is cutting back the foliage once the lobed leaves have nearly covered the surface of the containers. This reduces the incidence of rust in the greenhouse and is also an effective deterrent in the garden.