Q. I have a sweet autumn clematis vine that is all messy. It blooms beautifully. How can I "clean it up" and still have blooms?
A. The rampant grower that is sometimes called "Virgin's Bower" or sweet autumn clematis has a lovely scent and a rambling growth habit. It has a tiny white flower in luscious large groupings that produce a brilliant show of white blooms.
Clematis paniculata can grow 10 feet or more in a single season, and it blooms in early fall. This vine blooms on current yearly growth so it can be pruned hard and still produce flowers in the fall. However, it can become a tangled mess over time.
Like most clematis, the stems of this vine are very delicate. Once the light bark is loosened from a stem, the stem will often die back. Any wounds or cuts to the delicate stems can result in dead branches. Over time, the plant may consist of tangles of woody, brown, dead stems entangled with green growing stems and flowers. Older wood may produce new stems or may be dead. Hard for the gardener to tell which is which especially when the plant goes dormant in the winter.
If your plant is severely overgrown, you should be able to start from scratch. You can cut the entire plant back to a foot or so tall this winter. Trim back all the stems and place a rich compost around the root zone of your plant. Remove all the tangled growth.
In spring, watch as the new green shoots start to emerge and look into the clump of stems. The dried brown dead ones can be cut down to the ground and removed.
Pinch the new green shoots back to a branch node to produce heavily branched stems.
You can use this kind of dramatic cleanup every three years on rampant growers like Clematis paniculata. The process also works for the Jackmanii and viticella groups that bloom on new wood every year.
Email Pat Lea at lea.pat@gmail.com.