from: The Happy gardens Gazette – Spring 2013



Known for their spectacular flowers, attractive seed heads and vigorous habit Clematis can be a solid long term investment in your garden. There are some 250 species of Clematis as well as perhaps thousands of hybrids with flower colors ranging from white to pink to red, blue to purple and even yellow (C. tangutica). Finding one that suits your fancy should be easy.


Clematis prefer free draining, slightly alkaline soil, high in organic matter and very moist in early through mid spring, moderately moist through the rest of the growing season. The root systems require cool shade during the summer. You could use a strategically placed small shrub, a ground cover, large leaved perennial, large rock or tree stump to shade the root zone. Most clematis are at their best in at least 6 hours of sun per day but a few will tolerate, even thrive in shadier conditions. Try Nelly Moser, Hagley Hybrid, Elsa Spaath, Proteus, Lemon Chiffon, Silver Moon or varieties of Clematis montana, C. paniculata or C. viticella in shadier locations.


When planting Clematis bury the bottom 2 to 6 inches of the mature stem below the soil line. If the stem of your young plant is a little green, leave the final filling/ burying until the fall. A little bone meal mixed in the soil at the bottom of the planting hole will get them off to a good start. Pinch the stems back a bit to encourage branching. Water well and frequently. Be sure to provide good support for your vine right from the start. Fertilize your Clematis in mid spring with a granular 5-10-10 or similar fertilizer.


Many gardeners are puzzled about how to prune Clematis. Fortunately, there are some rules of thumb to help you decide when and how. Spring blooming Clematis are best pruned (thinned and shaped) immediately after flowering. Summer and fall bloomers are pruned (remove a few of the oldest, thickest stems) in late fall. Those that bloom in spring and again in late summer are only pruned to remove dead wood and correct shape.


A common malady of Clematis is Clematis Wilt. This disease affects the large flowered hybrids more frequently than the smaller flowered species. It frequently strikes in the first few years after planting often seeming to disappear once the plants have matured. If your vine quickly withers and seems to die, do not despair. The disease does not affect the roots and your plant will likely recover. Just cut the affected stems to ground level and dispose of them. Even if every stem seems dead your plant will likely send up new shoots though they may not appear until the following spring. Be sure to keep the area around your plant free of any plant debris that may harbor spores. A preventative sulfur spray before symptoms appear may be helpful.


A common question is how many Clematis do I need to cover....?  Most hybrids grow from 6 to 10 feet so one for a typical fan trellis is adequate, two for a typical gate arch. For larger trellises or arches, or to cover a fence, use one every 4-5 feet. Many species Clematis can grow from 20 to 30 feet so adjust accordingly.