I
have a full healthy clematis. I
cut it back to 6 inches in the fall.
The problem is it only produces flowers on the top.
Clematis typically flower towards the top of the plant. The lower stems are often intermingled
and shaded by the upper leaves.
Train stems flat against the trellis in spring as new growth
begins. This will increase the
light reaching the lower branches and encourage flowering lower on the
vine.