Released 04 July 1996; Updated 11 January 2005
by B. Rosie Lerner, Extension Consumer Horticulture Specialist
Looking for a vigorous climber that has a long season of bloom and can adapt to just about any garden soil? Sound too good to be true? Well, clematis pretty well lives up to the challenge.
There are numerous species and literally hundreds of cultivars of clematis, some of which are better adapted to Indiana's soils and climate than others. Unless you have extremely compacted and poorly drained soil, there's a selection that you can grow.
Clematis is a woody vine that generally prefers sunny locations with light, well-drained soils having average moisture and cool temperatures. A location that offers bright sunshine in the morning followed by light shade in the afternoon is ideal. Applying a mulch around the root area of this plant will help keep the soil temperatures cooler.
One of the first questions people ask about the plant is how to pronounce its name; is it clem-a-tis or clem-atis? The botanists would likely argue that clem-a-tis is the correct pronunciation, but most gardeners would understand either name.
The next most frequent question concerns the proper pruning technique for this flowering vine. How to prune depends on the particular species of clematis that is grown. To simplify, we'll consider two types of clematis.
Clematis that flower on last year's growth in spring and early summer. Examples include:
Duchess of Edinburgh
(* Will also flower on current season's growth if pruned in spring.)
Plants in this group can have either large, individual blooms or numerous clusters of small flowers. Because the flower buds are produced in the previous year, these plants should only be pruned immediately after flowering. Pruning in fall or winter removes the flower buds, thus removing the potential for bloom. In fact, Group One plants do not require annual pruning and may actually flower better if left unpruned for several years. If plants are badly overgrown and are in need of renovation, a severe, late-winter/early spring pruning may help rejuvenate the vine, but keep in mind that blooming that year will be sacrificed.
Clematis that flower on the current season's growth in late summer and early autumn. Examples include:
Comtesse de Bouchaud
Lady Betty Balfour
Ville de Lyon
(* Also flowers on last season's growth if old growth is allowed to remain.)
Plants in this group have a tendency to become bare at the bottom of the vine unless pruned annually in late winter. Cut these plants back nearly to the ground, leaving at least one pair of healthy looking buds on the trunk.
Clematis actually display several more types of growth habits than just these two simple categories. For the serious clematis enthusiast, a trip to the library or bookstore is highly recommended so pruning technique can be customized to the individual cultivar. In addition, here are some online information sources on clematis pruning:
International Clematis Society
Pennell's Clematis Nursery (U.K.) (click on FAQs, then Pruning)
Growing Clematis (Ohio State University Factsheet)
The URL for this page is http://www.hort.purdue.edu/ext/clematis.html