What is it about fall that makes folks think about pruning? Does it just
seem like the time of year to prune? Are you cleaning up sticks and
broken tree limbs and figure “Why not?” Is it the nice weather? I
know.your neighbor is doing it so you should be doing it too. That’s it!
Honestly, I say the best time to prune is when you’re ready to do it.
Otherwise it gets put on the backburner and pretty soon you can’t see
out the windows of your house because the shrubs figuratively ate them.
Having said that, if you care about whether or not your flowering shrubs
will bloom in the next season (and the health of the plants), then there
are a few other things to think about. Namely, what type of wood does
your shrub bloom on? There are two answers to that query: new wood or
old wood.
Plants that bloom on new wood can be pruned anytime. Their floral buds
are set on fresh growth so pruning may help manage the size of the
plant, but won’t greatly inhibit the flower display. A great example of
this is purple beautyberry (Callicarpa dichotoma). Left to it’s own
devices, it will easily grow 8 to 10 feet tall. But with regular pruning
(maybe even twice a year), it will stay less than 3 feet tall and still
have a beautiful flower and berry display in the fall. Examples of
plants that bloom on new wood include shrub roses, butterfly bush, and
rose-of-sharon.
The other option is plants that grow on old wood. I learned this lesson
the hard way after planting dwarf oakleaf hydrangeas (Hydrangea
quercifolia ‘Munchkin’) and Judd viburnums (Viburnum x juddii) in my
landscape a few years ago.before I knew much about critters,
specifically rabbits, and their destructive habits. There I was,
enjoying my newly planted beds from the kitchen window on a February
morning when I noticed that ALL of my plants had been pruned off,
leaving only sharp stubs of branches. I was angry, frustrated and really
sad that my plants may or may not survive. I was fortunate, all but one
viburnum survived. However, they only put on vegetative growth that
year, not a single flower. Bummer!
My solution to the rabbits was to make wire cages for each of my plants
(I have a small yard-it was doable). Again, and quite unfortunately for
the viburnums, I was a little late to the game. I managed to save the
hydrangea blooms and had a beautiful display this year, but I didn’t
beat the rabbits to the viburnum and I only had one single, solitary
inflorescence out of 10 plants this spring. I vow to get my plants
protected earlier this year.
My point, however, is that to preserve the harvest (so to speak), you’ve
got to know your plants and how they grow. If it’s on old wood, wait
until after the floral display to prune and then let them grow and set
new floral buds the rest of the year. Other plants in this category:
lilac, forsythia, flowering quince, mockorange, and spirea.
If you’re not too worried about getting a floral show within the next
year, go ahead and prune when you’ve got time. Especially if they are
overgrown. A good rejuvenation pruning for shrubs can often do wonders
in the landscape.
All of this advice applies to deciduous shrubs. Evergreen shrubs and
trees are a whole different ballgame. If you’re interested in learning
more about that type of pruning, check out your local Extension
resources or our K-State Horticulture Information Center website
(http://bit.ly/KSUHortInfoCenter).
It’s worth noting that, while lots of folks are thinking about pruning
now, it may not be the best time for many shrubs. I’ve read several
predictions that we might have a nice long fall (Yay!) and if that’s the
case, newly pruned shrubs may put on a flush of growth that won’t have
time to harden off before winter strikes (and this one may also be a
doozy). The best way to avoid this kind of damage is to just wait until
late winter or early spring to do your pruning. Ahh!-a good reason to
procrastinate.

By: Cheryl Boyer