Cultivating Clematis

"I encourage people to grow the summer-growing clematis because they're the easiest ones to care for," says clematis expert Maurice Horn.

Broken or damaged stems can of course by cleaned up, but before you prune aggressively, know the particular requirements for the particular cultivars you've planted.

Horn selects 'Negritianka' because of its very dark bloom. He removes the garden tape from the stake for easier access to the stems and makes a cut just above a leaf axil (figure D). Next, he mixes lots of organic compost--at least two inches' worth--with the native soil. Into the planting hole the plant goes, along with a stake or trellis. He then covers the plant with soil so that it's positioned deeper than it was in the pot. He ties the stems back to the stake loosely (figure E), and then waters thoroughly.

"Those of you that live in Northern climates can plant clematis deeper than I would normally plant them here in the Pacific Northwest, which is a very mild climate," says Horn.

Combining with other plants is just one example of how this wildly versatile plant can be used in the landscape, especially, when you consider that many, like this clematis (figure H). The species Integrifolia, which is hardy in USDA Zone 3, do well in some of the colder parts of the country. "Most of the large-flowered hybrids that I've shown you are hardy down to Zone 5, and a few are hardy down to Zone 3," says Horn.

So if you're clamoring for clematis, check what's available in your local nursery or garden center for a good indication of which plants will grow in your area. When purchasing clematis, find established plants with lots of stems (figure I).

"I always look to see if the plant has filled out its roots to the base of the pot, as with these nice golden fibrous roots at the base (figure J)," says Horn.

When the flowers fade (figure K), twirly, curly, silver seed-heads form to give the plants yet another month of interest in the garden (figure L).

Another interesting thing about clematis is that they have remarkably few pests; earwigs and slugs love the new spring growth. Horn's slug solution: roll up a newspaper and place it at the base of the plant at night. Then, trash the newspaper in the morning after the pests have crawled in for a nap.