Use these tips for pruning rhododendrons to get a burst of fresh foliage and flowers.
Although generally low-maintenance, rhododendrons occasionally do need pruning to rejuvenate them.
Timely pruning can bring a long-forgotten plant back into a pleasing shape and size.
Credit: Bob Stefko
But a very overgrown rhododendron needs a different pruning game plan.
Take a minute to assess the state of the shrubbefore grabbing your pruners.
Pruning does not help a struggling rhododendron overcome challenging site conditions.
Plants growing infull sunorheavy clay soilwill continue to suffer until they are moved to dappled light andwell-drained soil.
Pruning only further stresses a plant growing in poor site conditions.
When to Prune Rhododendrons
Experts agree thathealthy rhododendrons require little pruning.
These shrubs dont respond well to an annual hard pruning the way other woody plants might.
In fact, rhodies tend to produce fewer flowers when pruned too much.
If you must prune a rhododendron to limit the size, do it inspring right after the plant blooms.
Grabbing your pruners when you spot a dead, broken, or diseased branch is also important.
Cut the branch back to the closest healthy branch.
Occasionally, dead, broken, or diseased branches need to be cut back to ground level.
A few short, compact cultivars include Landmark, Bubblegum, and President Roosevelt.
Thebest time to prunean overgrown rhodie is spring, right after the shrub blooms.
Use this year-by-year technique to avoid stressing the plant too much.
Year One
Begin by removing any dead, diseased, or broken branches.
Look for branches rubbing on one another and remove one of the offenders.
Also, keep an eye out for branches growing toward the interior of the plant.
Cut out weak, spindly wood, pruning branches down to ground level as needed.
Next, reduce the overall size of the plant.
Determine the desired size of the rhododendron when the pruning is complete.
In year one, reduce branch length by about one-third to move toward the desired size.
Cut only a few overly long branches back to ground level to create the most natural shape possible.
In years two and three, youll move toward the finished size.
Year Two
Flowering will likely be limited this spring after the significant pruning last season.
In late spring, remove any dead, diseased, or broken branches from the previous growing season.
Then, prune to reduce the size of the shrub, removing no more than one-third of the growth.
Year Three
Year three is the last year of major pruning.
Healthy plants will suffer less weak or damaged branches that need to be cut off.
