Clematis generates a lot of interest this time of year, generally because of its showy flowers. This member of the buttercup family is capable of living for 30 years or more, but its culture and care aren't well understood in our climate.
The major breeding ground for these somewhat woody, vigorous-growing vines has classically been England. But clematis vines perform well here in spite of their natural preference for the evenly cool weather conditions of Britain or more mountainous regions of the world.
The enigmatic aspect of how to care for clematis is that, depending on the variety, it could be a bloomer any time during the growing season. There also are at least 1,000 hybrids from more than 200 species, said Edith M. Malek, president and founder of the American Clematis Society. So there's not a simple answer to all of the questions about care and pruning, but here are some general guidelines offered by Malek and others.
Plant clematis in spring or fall, where it has shaded, moist, well-drained soil for the roots and full sun for its foliage. It can be planted now if you can find a vine growing in a container at a garden center. Plant the vine deep into the soil in a hole that's dug 18 to 24 inches wide and deep. Amend with 20 percent to 50 percent compost. Plant the stem of the vine five inches underground.
Feed the plant when the new shoots have grown two or three inches long. Malek prefers to use an organic rose food. Other experts recommend organically based tomato fertilizer. I'd say that any balanced food that's low in nitrogen and high in phosphorous and organic content will encourage flowering. Don't let fertilizer contact the plant leaves.
Water often. Don't let clematis dry in the summer heat. Mulch it with compost or other organic material to hold moisture, but don't mulch against the stem. Prune selectively to control the growth or shape of the plant, but don't interfere with flower-bud production.
Pruning of clematis isn't necessary unless you need to control the run of the plant. And, if it flowers in spring, don't prune the winter stems at all. That's where the flowers come from.
The following are some varieties that will make a wonderful show in your garden:
* Constance. Alpina type with bright red flowers; thrives on a trellis; flowers as soon as weather warms in spring.
* Betty Corning. A pink, scented flower; blossoms from summer into fall.
* Etoile Rose. Vine grows to about 10 feet; tulip-shaped pink flowers from summer to autumn.
* Continuity. A montana hybrid; vigorous, will grow to 16 feet; produces deep-pink buds with yellow anthers almost continually from spring to early fall.
* Vera. A pink, strongly scented montana hybrid; will grow 35 feet tall; profuse flowers in spring.
* Nelly Moser. Raised in France more than 100 years ago; large pink and white flowers; one of the most popular.
* Jackmanii. Some of the most famous clematis in the world. Jackman A.G.M. has four-inch purple flowers; alba is a white version; jackman rubra is red and larger than the others. Will bloom from spring to fall.
Before planting clematis, you should read about them and see their blossoms at your local garden center. Three texts were published this year, and each book handles the subject in a little different way. All are good, much needed and you can own all three for less than $50.
The best summation of clematis culture that I've seen is the American Clematis Society's "Guide to Growing Clematis in the United States" by Edith M. Malek. It's a concise, practical guide for American gardeners who have only been able to get information from British authors' points of views. Color plates are included with the society's suggestions of 48 clematis for your garden. You can get it for $19.99 by calling 949-224-9885 or on the World Wide Web at www.clematis.org.
Another paperback for excellent visuals and how-to advice is the handbook "American Horticultural Society Clematis" (DK Publishing, $8.95). Author Charles Chesshire breaks the extensive list of clematis into pruning groups.
The best reference book is "Clematis for All Seasons," by John Feltwell (Firefly, $19.95). Feltwell focuses on excellent photography, good companion plants for clematis and breaks out varieties by color, group, care and much more. He then lists more than 400 species and hybrids by name and description, which covers about 40 percent of all named varieties.
Even given general suggestions for care, each species is unique. Clematis can be a temperamental vine. It can wilt and die in what we think is the perfect environment or can become an invasive weed in a completely inhospitable situation. Ultimately, it's the clematis that decides where it's happy and where it's not.
Lerner is president of Environmental Design in Capitol View Park, Md. His e-mail address is firstname.lastname@example.org
Shopping for Plants
* Always buy the biggest plant possible. I would not recommend anything smaller than a two-gallon plant. Five-gallon plants are preferable because you are more likely to get a well-established plant with a bigger root ball and the wholesale nursery has done the early training for you.
* Always look for strong, thick and undamaged stems. The thicker the stems the better.
* Always buy a healthy plant. Do not buy a plant just because it's low-priced.
* Always buy a named cultivar. Make sure the tag has the full scientific name on it. If the label just says "Purple Clematis," don't buy it. You will have no idea how to prune it or what size it will become.
--From "Guide to Growing Clematis in the United States" by Edith M. Malek