Can I Prune or Cut Back This Plant Now?

Can I Prune or Cut Back This Plant Now?

In the fall, people often wonder if it’s okay to prune shrubs or trees. Perhaps that plant has grown quite a bit in the summer, or maybe it’s been on their mind for awhile but they haven’t gotten around to dealing with it yet. No matter what the reason, we hear our customers ask if they can cut bushes and other plants back at this time of year. Our answer is, “It depends…” Here are some examples of typical fall pruning questions.

My Rhododendron is too big…can I cut it back now?

There are several ways to deal with the too-large Rhododendron. In fact, we’re writing a handout on this very topic that will be available on our “Informational Handouts Page” soon. In the meantime, know that if you trim your Rhody back in the fall you will be removing the flower buds for next year. The better time for a light pruning would be right after it flowers next season. If all you’re doing is removing 6 to 8 inches, you won’t be doing other harm by trimming now, but any substantial pruning should be done next season.

Rhododendrons form their flower buds in the summer for blooming the following year. So pruning them in the fall removes those buds and the plants won’t flower the next spring/summer. This Calsap Rhododendron flowers in late-May, so would be best cut after that.

My arbrovitaes are too large. I want to trim them now, okay?

If you’re shearing an inch or two off the outside of your arborvitae (Thuja species and hybrids) you can do that just about any time. But be careful! If you cut too far into these plants they do not respond with new growth. Never expose bare wood on an arborvitae. If you do, it will not regrow in these areas.

This is an example of an arborvitae that was pruned back too far in order to keep it off the house. The plant has remained bare on that side for several years, and will continue to look like this into the future.

My shrubs are out of control. My landscaper says we can “cut them down hard” now and they’ll come back. True?

The type of pruning you are describing is a renovation pruning, and you should never do this in the fall, no matter what kind of shrub you have. Wait until spring for any major cutting back of shrubs. For more information about this, register for C.L. Fornari’s virtual talk about pruning on September 25th.

These shrubs were cut back hard in the fall. Not only do they look like Halloween decorations now, but they only partly came back in the spring. They never looked decent again, and after two years of waiting they were removed.

Can I cut back my Leyland Cypress now?

Yes, you can trim Leyland cypress in the fall, but many people wait until later in November so they can use the branches for holiday decorating. Ideally, these plants should be trimmed back every single year to keep them bushier and fuller. Shear between 6″ and 18″ off all long branches except the leader as long as you want them to be taller; once they are nearing the height you want them to be, shear the entire plant every year. This does not stop them from growing (eventually you’ll need to hire someone with ladders or a bucket truck to trim them) but it will help them to stay the thick screening you wanted them for in the first place. Leylands can be trimmed fall, winter or spring.

These Leyland Cypress haven’t been sheared regularly and that’s why they are becoming thinner on the bottom. Additionally, the dead branches are unsightly. Trim these plants before they need it, and do so every year.

My Hydrangeas are too tall…okay to cut down now?

Here’s the news you don’t want to hear: if you trim these shrubs down to make them shorter, either now or in the spring, you’ll have far fewer flowers next summer, and, the plants will be just as tall by July as they are now. There is no way to make these cane-growing shrubs shorter. If you don’t like them growing so tall where they are located, move them and plant other varieties of Hydrangea or other shrubs in their place.

These Nikko Blue Hydrangea shrubs naturally grow to 5 o 6 feet tall on Cape Cod. If they are cut back there will be few flowers next summer, and the plants will be just as tall by July. They replace their growth in one season.

I’m trying to keep yews off of the walkway. Cut now?

Yes, non-flowering evergreens such as yews can be pruned in the fall or winter if you’re only taking a few inches off. But if you are planning to renovate them, wait until spring. Additionally, ask yourself if fighting their size by a walkway is really the best use of your time. Maybe this is your opportunity to remove those plants and decide if there would be a more attractive planting for that area. We can help with your design questions! Read about our consultation services here.

There comes a time when the neat, small hedge you planted several years ago is not as attractive and is just too large. Fall is a great time to remove such plantings and prepare the area for something else.

Is there any pruning that is always safe now?

It’s always safe to remove dead stems and branches. So if you can tell that something is dead, cut it out any time. Plants that don’t flower in the spring are safe to trim a little bit now, but any major pruning should wait until next season. Woody plants store energy in their stems that they use for winter survival, so removing much of their growth now isn’t the best idea.

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