Clematis is easy to grow with a long season of bloom and some of the plant kingdom's most beautiful flowers.
If you're already a clematis grower, you know all this. But if you're not, here's all you need to know. First of all, there are several kinds of clematis, but most people want to grow the large-flowered types. For some info on the others, go to the bottom of this page.
In Vermont, most large-flowered clematis bloom from early July all summer long into September. But the varieties vary; check the individual information on each clematis page. Always deadhead the flowers as they fade, and you'll have a magnificent display for months.
Planting and Mulching Clematis
Clematis vines always want their roots shaded, and the plant growing up into full sun. That means you can put some shallow-rooted groundcover around the roots, or simply some mulch—just something to keep the hot sun off the root run, and promote moisture retention in that spot.
Just be sure your vine grows into plenty of sunlight, which promotes heavy flowering. Soil is important. Clematis do best in neutral or slightly alkaline soils, but they are somewhat adaptable. If you have very acid soil, try to add some calcium when you plant. Also, be sure to dig the hole deep. Remember you're planning to have this plant in place for decades.
Where to plant is important. These incredible vines are some of the most beautiful flowering plants, and we've all seen them blooming lavishly on fences, porches and trellises. They're not really hard to grow, and they get larger and stronger every year. Sometimes they take their time getting going, so be patient. It usually takes about two years for a newly-planted vine to come into its own. The large-flowered types are hardy into the very cold north, so almost everyone can use them. Be sure to place yours so it has something to climb — fence, trellis, or post.
For clematis, winter and spring care are important. In the spring, wait until the stems show green sprouts. Then, it's usually a good idea to remove the weaker old wood. Remember, many clematis bloom both on old stems and the new, so don't remove everything. Instead, leave the main stems of the old framework that show sprouts, and remove the thinner smaller stems above them. This way, your sprouts will grow into strong new growth for the coming bloom.
In very cold places (like Vermont, where I grew them for years), the winter kills the whole vine right down to the dirt. They actually "disappear." Then in the spring, they are somewhat slow to emerge, so you must protect the spot, and watch for the shoots. Once they pop up, they grow fast, but beware—they are brittle! If you happen to break off the young spring shoots, it sets the vine back terribly, so it's important to watch and care for the new shoots until they really get going up your post or trellis.
Once that happens, it helps to gently guide the vining shoots as they find their way upward. You can actually "arrange" your vine as it grows, but again, be gentle; the stems remain brittle. Soon you'll see buds, and then suddenly one day, they begin to open. Most popular clematis varieties open incredibly large flowers, often as large as 5 to 8" across. They face the sunniest side of your trellis, and well, just take a look at the photos. Nothing makes a lovelier display.
Fertilizing and Care of Clematis
Nicholas Hall, the man in England who was in charge of the National Collection of Clematis during the 1990s, suggests the following:
When planting a clematis, mix in some good organic material — say, potting soil or peat moss, and add a handful of fish, blood or bone fertilizer. (I never use bone meal, since I've had too many plantings dug up by dogs thinking they've found a bone!) Well-rotted manure is great at the bottom of the hole.
Watering is all important in spring. After the spring rains, clematis are growing so rapidly they usually need extra water. Mr. Hall suggests an extra bucket full every few days, even if you're having rainstorms. At this time, he also suggests adding tomato fertilizer at the recommended rate at this critical time for your vine.
After bloom, if you choose, you can reduce the size of your vine partially, which will mean a little less work the next spring.
Other Types of Clematis
The wild North American clematis, commonly called "Virgin's Bower" has small "frothy" white flowers that cover the large vine. The Montana types have smaller flowers than the large-flowered ones, but they create a much larger mass of vine. Montana clematis are wonderful for covering a roof or large area of fence.
Unfortunately, both Virgin's Bower and Montana clematis are limited to central and southern zones, not hardy in the far north like the large-flowered favorites.
The Viticella Group, sometimes called the Italian Clematis, has vines similar to the Large-Flowered group, but usually forms a larger mass and has very heavy bloom of somewhat smaller flowers.