Ask a friend to name a favorite flower or vegetable and chances are, you'll hear of tomatoes, impatiens, marigolds, peppers, geraniums, corn or any one of the dozens of annual plants Americans grow in their summer garden.
But ask about a favorite vine and you'll probably see a look that repeats the question: "Favorite vine?"
Give a few hints and you may well hear clematis. It is hard not to like clematis, a perennial vine that grows 3 to 20 feet tall and is at home in most U.S. climates.
What is striking about clematis is the size and color of its blossoms. Some reach up to 6 inches across and the colors are stunning -- deep blue, deep rose pink, mauve-pink, soft violet, dark red, indigo blue, reddish-purple and white. It's not quite a rainbow, but close.
What makes this perennial vine so popular is its versatility in landscape situations. It can climb fences, mailbox stands, and lampposts. It is splendid for hiding a tree stump that is slowly decaying or to bring color and accentuate form to an otherwise barren trellis, teepee or pergola. It simply provides wonderful color and cover in many areas of the garden.
As perennials go, it doesn't look like much at the nursery. Potted or bare-root, it usually looks like little more than a few twigs. All it needs is time to be splendid.
Like peonies and a few other perennials, clematis can be a long term resident in your garden, so it makes good sense to provide the right conditions before the roots even get a look at the soil.
Clematis is a native of southern Europe and its name is drawn from the word klema, or vine-like, a reference to the growth habit of most the 200-plus species in the genus. What is striking about the plant is the contrast between its dark green leaves and brightly colored flowers. Like many plants, it has a few other names -- old man's beard, traveler's joy and virgin's bower among them.
It does best in soil that is cool, rich, moist and well drained. When planting, dig a hole twice as big as the existing rootball and amend it with compost or sphagnum peat moss -- say, half native soil, half amendment. The vine needs full sun but the roots like things cool. This is easy to accomplish by an underplanting of ground cover or even easier, a 3-inch blanket of organic mulch like wood chips or bark covering the root zone.
Pruning and patience are probably the two trickiest components in caring for clematis.
Patience comes in understanding that the plant needs two or more years to get established before it begins to vine and bloom vigorously. Once established and is in a good location, it is dependable and beautiful.
Pruning can trip up even the most experienced gardener. The best time to prune depends on the nature of the variety's blooming pattern. Clematis can roughly be divided in three camps: Large-flowering hybrids, late bloomers and early bloomers. Knowing when the particular plant blossoms is the key to successful pruning, and that is the path to successful flowering.
Hybrids are probably the most popular of the clematis because of the size of their flower. They are best pruned when the plant is dormant; in areas that experience snow this means by the end of March. Dead and weak stems should be removed and live stems cut back to the first set of green leaf buds. This type can often be "re-bloomed" in the same season by cutting the vine back to 18 inches or so after the first flush of bloom.
Clematis that bloom late in the season, such as in August and September, should also be pruned back in winter to a height of about 3 feet. These flower on the current season's growth.
Types that bloom in April and May are considered early bloomers and these produce flowers from buds that were formed the previous season. It is best to prune soon after they have blossomed as doing so will give the vine time to make new growth this growing season and thus, flowers for next year.
Most clematis climb handily and do so best when support is thin or wire-like (but not real wire). This is because the plant climbs by its petioles twining around support, and they are not able to "grab" conventional trellis or thick branches. This doesn't mean you can't use a conventional trellis or pergola, just that the clematis will climb better if you also provide a wire-like "skeleton" for the petioles to grab. Net-type materials, typically made from plastic, are readily available at garden centers.
About the only pest that bothers clematis is a disease called stem rot or leaf spot. It is common on large-flowering varieties. What is weird about it is that it comes on all of a sudden, usually when the vine is at its peak foliage performance. It is hard to miss, as one or more stems turn black within a few days. It seldom kills the plant and is easily treated by removing the diseased stem to a point just below the wilt area, even if this means going an inch or so under the soil. It is important to remove the entire stem as soon as its presence is apparent.