Pruning Redbud Forest Pansy & Climbing Clematis

(Question)

My redbud forest pansy was planted three years ago. This spring we had hardly any little blooms on the branches and the tree started to leaf very late with some branches dried up. We had a tremendous growth spurt afterward and many long thin branches shooting out 3 to 4 feet from the main trunk. We would like to know when to prune these branches back and how much, and will it cause a problem with the spring bloom. We also have a clematis that wraps around the tree with substantial growth throughout the season with beautiful pink bell-shaped flowers, and we would like to know if it’s harmful to the tree.

(Answer)

Lucky you to have a Cercis canadensis ‘Forest Pansy’. The tree blooms with lovely rose-purple flowers on bare branches in the early spring, even before leaves emerge.

Pruning should be done in late spring, just after blooming. If you prune the tree now (it’s November) or in the winter, you risk reduced flowering. However, simply getting rid of a few unsightly branches should not affect the spring blooming.  As it was a  rough year for redbuds, though, you may want to leave the tree alone until spring.

When pruning thicker branches do so to just above the raised area that’s right above the crotch of two branches – this is the “branch collar”. For small branches, like those you describe, prune either to the collar or to a terminal bud or branch. Remember to disinfect your pruning tools with rubbing alcohol before & after making cuts. For small branches up to 1.5 inches in diameter, use lopping shears.

And how lovely to have a clematis happily growing up the redbud tree. Any vine growing up a tree trunk can cause structural problems for the tree – e.g., the additional weight can lead to broken branches, and more snow/ice may be deposited.  The vine can also decrease the amount of sun the tree leaves receive.   Leaf debris from the vine near the tree’s roots could promote fungal/bacterial disease by trapping moisture. Some vines (not clematis) can even strangle the trunk & tree limbs.

Clematis is considered to be a relatively slow-growing vine, so should be fine growing up your tree. As long you prune the clematis each year, it should not grow too large or heavy to damage the tree. A suggestion is to let the clematis grow as much as it wants through the summer, then prune back any portions that extend into the tree branches – keep the plant confined to the trunk area of the tree. And make sure there is no plant debris/leaves on the ground against the tree. And in case you want information about pruning this lovely vine, see the Pruning Clematis  overview on our website.