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What’s the best time to prune? Hint: Not this month

Oct. 22, 2018


A few inquires about pruning have come my way lately. Perhaps it was election stress that has people reaching for the loppers and pruning shears. But this is not the time to take out your frustration — even your anger — on your landscape. It may seem like a good time, but on the whole, it is not.

Take monkey grass, for example, One reader asked if it is time to prune this ground cover. Another reader is keen to cut back Knock Out roses. Plus there’s always an inquiry about ornamental grasses, their plumes still rising prettily.

A lot of this, I think, comes from the notion that the garden year closes down about mid-November, when thoughts turn to shopping and decorating. Yet, here in the Piedmont, it really doesn’t close down, though darkness falls really early these days.

The traditional caution about late summer, early autumn pruning is that it will stimulate fresh growth that will remain too tender when really cold winter hits. That is something to remember, particularly with plants like gardenias, because there is sometimes a risk of a really deep freeze in early December. But that doesn’t happen very often.

I think most people have learned to prune important flowering plants, such as azaleas, rhododendrons, gardenias and forsythia after their bloom ends in spring. And only the spent flowers of hydranges and their little stem that attaches them to the main stem should be cut off now.

The puzzle starts with more ordinary things that we have around, such as Japanese hollies along the front of the house and monkey grass used as a serviceable edger or ground cover. The thing to remember is that when you prune a plant now, the result is how it will look until it begins growing in spring. This is not a problem when you are only pruning a wayward stem to make the plant more pleasing in appearance or keep it from hitting cars or people. Plus, there should be no harm in cutting stems of hollies, nandinas, cedars and boxwoods to use at Christmas in wreaths and flower arrangements.

But overall pruning and especially rejuvenation pruning, which is quite drastic, should wait until just ahead of the growing season, about late February.

The plumes of ornamental grasses tend to look good well into late autumn, even winter, so they can remain in place as long as they appeal to you. Some become shabby faster than others so just keep an eye on them.

Monkey grass blooms in late summer, and the flowers linger a while. But monkey grass is an exception to the prune-after-bloom rule. That is because if you prune it now, either by mowing with the blade set at the highest level, cutting with a string trimmer or using a shearer with long blades. Done well in late February, this looks like a flat-top haircut and not too pretty. But growth soon emerges to give a fresh new look. This is not something that has to be done every year, but only when the older leaves start to look worn or weather-beaten.

 


McClatchy-Tribune Information Services