Clematis

By Cathy Krar, Master Gardener In-Training, SCMG

The ultimate goal of gardening is NOT the growing of plants … but the cultivation and perfection of human beings.

I adapted this phrase from The One-Straw Revolution by Fukuoka (P. 119.)  He refers to farming, but I feel the same is true of working in gardens, especially when working with clematis.

This year I found myself surrounded by many varieties of clematis: Viorna, Alionushka, Crispa, Betty Corning, Terniflora.  I realized I wanted to learn more about these vertically amazing vines.  I also realized that my own growth and cultivation was being impacted as I quickly developed a fascination for these “Princesses” in my midst, and wondered about the best way to tend to them.

Clematis viorna

I learned there are generally considered to be 3 classifications of clematis, with Group 1 blooming on last year’s wood, and might need very little pruning after they flower.  Alternately, you could leave them alone, and give them a hard pruning every 3 to 4 years.

Group 2 were the large flowered Hybrids like Henryii, Jackmanii, or Hagley Hybrid. In Gardening Grief & Glory, Ed Lawrence (p. 251-252) suggests pruning the hybrid varieties like Jackmanii to about 2 feet in the fall and then cutting off branches that have been winter-killed in the spring.  Jackmanii can be pruned to the ground or within a couple set of buds.

Now, there are always exceptions to every rule, and the Nelly Moser variety that I will mention is a larger hybrid,  but really belongs in with Group 3.  She doesn’t want to be pruned to ground level.  Nelly Moser flowers on last year’s growth in early spring; and again in summer on new wood growth.  Prune this clematis early in the spring to revive weak or dead vines.  I specifically mention this one because I purchased one in July to plant at the southwest corner of my own home. Group 3 usually have smaller flowers  and need very little pruning.

Some clematis bloom in semi-shade, but most prefer a sunny location with 6 hours of sunshine being ideal.  They require moist well-drained soil conditions though.  I also learned that Clematis are voracious feeders and should be fed spring through to the fall.  It seems they enjoy an occasional infusion of coffee grounds mixed with a little wood ash around the base.  Not too much or too close, or the plant can receive a nasty nitrogen burn. You can also fertilize every 3 to 4 weeks, but do no overfeed, or you will create leggy growth and the stems become quite brittle.  (Clematis enjoy compost, bone meal or rose food).

In planting any clematis, it is a good idea to plant them 3 inches lower than most plants typically enjoy.  This will encourage faster clematis growth and keep the roots cool in the process. They like delicious soil and mulch at the base.  The lower planting level will protect clematis from frost and also from any fungal diseases.  It will also promote more buds under the ground.

I checked out several websites that recommended having pencil thin trellises so the petiole or stems can coil around.  They are very fragile, so you need to take great care in attaching them to a trellis with velcro tape or loosely tied twine.  Wire is never recommended or you can break the stems.  Once the petioles have taken hold, you can remove the tape or twine (see www.thegardeningtutor.net or The Impatient Gardener on Youtube).

Instead of a trellis, you can use natural ways by planting under a hydrangea or a hedge for your favourite clematis to climb up.

After reading Brian Bixley’s new book, Minding the Garden, I fully intend to seek out more of the Group 3 varieties.  He mentions that they are smaller and less showy, but also much less temperamental than the larger flowering hybrids. (Betty Corning is at the top of my list). (p. 141-143)

What I essentially learned in all this is that pruning or not pruning clematis is NOT an exact science.  Clematis are quite forgiving if you care for the roots.

Clematis viticella