April 20, 2006 © Janet Davis
Sometimes we can be a little too conformist
in the way we design with plants.
In our borders, we place all the short plants in front and the tall ones
at back, creating an orderly arrangement that’s anything but natural-looking. We don’t dare mix magenta and 
orange,
even though nature tosses colours together with abandon. We arrange the same perennials in
groups of 3’s or 5’s because some designer said that’s the way we should do it;
it certainly wasn’t Mother Nature, who doesn’t count plants. As for vines, we carefully train them to grow up
traditional trellises to keep them neat and tidy and away from other
plants.
It might be shocking to hear this, but nature abhors a trellis. In fact, nature doesn’t “train” vines at all. Out in the big, bad world, vines just do their thing: gambolling through groundcovers, creeping over rocky outcrops, twining around nearby shrubs and scrambling up tree trunks.
One vine that benefits from a more relaxed treatment is clematis, which can be allowed to grow up through trees and shrubs, especially spring-flowering species like forsythia, magnolia, mock orange and crab apple. As long as summer-blooming clematis like purple ‘Jackmanii’ or pink ‘Comtesse de Bouchaud’ are used, it gives the spring-flowering hosts a second period of interest long after their own blooms fade.
It’s important in this case to know the
pruning needs of the clematis because this only works with the types that are
pruned right 
back
in early spring, not the early-blooming cultivars like ‘Henryi’ or ‘Nelly Moser’
which flower on old growth and must be left unpruned. Also, it’s important to ensure that the
clematis is planted 60-90 cm from the root zone of the host plant, thus giving
both their share of nutrients and water.
In my garden, I grow clematis several ways. Deep purple Clematis ‘The President’ has its own traditional fence trellis. Clematis fargesioides flings its 8-metre long stems and froths of small, white summer blossoms over the top beams of a deck-borne pergola. Clematis viticella ‘Polish Spirit’ flowers through an airy armillary sphere set atop a 3-metre high metal obelisk. I also pair clematis with host shrubs and climbing roses. ‘Etoile Violette’ hitches a ride on Rhododendron ‘PJM’, providing deep purple flowers in summer long after the rhodo’s star turn is over and ‘Hagley Hybrid’ throws its mauve-pink blossoms over a clipped boxwood shrub and up into a ‘New Dawn’ rose near the front steps. Other good clematis hosts are yew, cedar and juniper.
Clematis can also be left to their own devices in an informal border where they’ll romp through perennials and grasses, creating interesting combinations. At the delightful Brickman’s Country Gardens in Sebringville, near Stratford, I was charmed by Clematis tangutica with its yellow lantern-like flowers scrambling through an August border alongside purple coneflower, Joe Pye weed, helenium and blue lobelia. And at the Conservatory Garden in New York’s Central Park, non-twining Clematis x durandii shows off its violet blossoms atop a burgundy-leafed Japanese barberry.
Adapted from a column that appeared in the National Post