Ask The County Agent: ‘Do I prune my landscape plants this time of year?’
By Stephanie Butcher, Coweta County Extension Office
QUESTION: “Can I prune my landscape plants this time of year?”
AGENT: There isn’t a one-size-fits-all approach to pruning. The answer to your question is … ‘it depends.” Whether or not you should prune a particular plant right now depends on the specific plant you are wanting to prune.
Several years ago, a client came into the Extension office and exclaimed, “I need help with my hydrangea. It hasn’t bloomed in years.”
After talking with him for several minutes about his plant, I learned that he had soil tested, fertilized and made sure the plant received the right amount of water and light. Then he said in exasperation, “I even prune it every year too.” Bingo!
There are several species of hydrangeas. Some of them bloom on “old wood” (bigleaf hydrangeas) and some bloom on “new wood” (panicled or smooth hydrangeas). He was pruning at the wrong time. His hydrangea bloomed on old wood, so when he pruned it in January each year, he was pruning off all of the buds. He smiled and said jokingly, “So basically, you’re telling me that I’m an idiot.”
He was always joking, so we both got a big laugh. I explained that the time to prune his hydrangea was soon after it finished blooming. He left the office that day with a big smile and felt a little smarter than when he arrived.
The time to prune summer-blooming plants and most woody ornamentals is January through early March.
Some of these include:
Chaste tree (Vitex)
Rose of Sharon (Althea)
‘Anthony Waterer’ spirea
You need to prune spring-flowering plants like azalea, forsythia and dogwood soon after they bloom. If you see dead plant material though, then you can prune that off any time of the year.
Pruning is as much a science as it is an art. It’s often necessary for a plant’s health. It can remove disease, keep the plant looking good and rejuvenate older, overgrown shrubs.
Here are some basic techniques that can help novice gardeners avoid mistakes with pruning that can cause lasting damage.
Use the proper tools
Hand-operated shears work just fine as long as you keep them sharp. You want them to cut the plant instead of tear it.
Hand pruners are perhaps your most essential pruning tool. Buy the best quality you can afford so that you won’t have to keep going back to the store for a new pair every year.
Use lopping shears to prune small trees or shrubs, like crape myrtles, with a branch diameter of up to 1.5 inches. For plants with branches more than 2 inches thick, use a pruning saw.
Heading or thinning
There are two pruning methods: heading and thinning.
Heading is when you shear across the plant non-selectively. You might see this used on boxwoods or other hedge plants to give them a “formal” look.
Use heading sparingly. It causes new growth to grow back too thick preventing air and light from reaching the interior branches of the shrub.
Thinning is more useful and will lead to a healthier shrub in the spring. Use thinning to prune out sections of the plant. This allows more light and air inside, which can reduce disease and insect damage.
Shape the plant
Always leave the bottom of the plant larger than the top when pruning so that the plant forms a pyramid shape.
Make your cuts at a slant and at a fraction above the bud. The slant will allow water to roll off the newly cut surface.
Don’t use pruning paints since they are unnecessary and may slow the cuts’ healing process.
Complement pruning by going easy with the fertilizer. You want your plants to put any stored energy they have into healing, not into sending new shoots.
For more information about pruning or to inquire about upcoming hands-on pruning classes, email [email protected] or call 770-254-2620. Ask for the UGA Extension publication, “Basic Principles of Pruning Woody Plants”.
The University of Georgia College of Agricultural & Environmental Sciences is an equal opportunity, Affirmative Action, Veteran, Disability Institution.
Photo credit: UGA Cooperative Extension