I have an overgrown Mugho pine in my front border. Is it okay to prune it?
Mugho pines are highly variable “shrub” pines that often end up in residential gardens where full grown pines just won’t fit. And why not? Their compact form supplies structure, winter interest, and pockets of deep, spiky green that make perfect backdrops for splashy flowers.
Still, no plant is perfect and one of the challenges of growing Mugho pines is the great variation for which the species is known. Some of these pines remain tight, compact, and prostrate as they mature while others sprawl, shoot for the sky, or send up periscoping branches in the most unsightly places.
Most Mughos sold in garden centres these days are the dwarf varieties and you can reasonably expect them to grow five feet wide and almost as tall. However, not all Mugho pines conform and you have no idea when you purchase one whether it will hold true to the normal maximum dimensions, grow to swallow your garden shed, or develop into something that looks like it might have been meant for some cheesy horror film.
Pruning a pine - any pine - can be quite the challenge. Frustrated gardeners have been known to turn their hedge sheers on their Mughos in order to make them look like the cute balls they were never supposed to be. Unfortunately, they tend to look like roadkill forever afterwards. And removing entire branches often leads to conspicuous blank spots that never quite grow in.
What I'm trying to say is, if you let your Mugho pine get to the point where pruning is necessary, you’re probably going to end up with a butchered mess. It's better at that point to just pull it out.
So then how do you prune your pine without creating a local landmark of wretchedness? You do it by pruning it annually from the time you first plant it.
Each spring, pines push out bright green new growth, known as candles, from the tips of existing branches. Once these candles have fully extended, you can cut them in half without destroying the look of the plant. Doing this every year will slow down the growth rate of the plant and force it into a more compact form. It will also allow you to tweak the overall shape of the plant by cutting some candles a little shorter than others, effectively correcting minor deviations before they become major eyesores.
If you have a lot of candles on your mugho pine - something that's very possible if you've been diligently pruning them each year - you may want to snap the candles in half with your fingers, which tends to be much quicker.
Ultimately there is only so much you can do to control a pine's growth. If you have the misfortune of dragging home a Mugho that's destined to grow to record setting heights, all the candling in the world won't keep it in check and you will either need to learn to live with it or you'll have to pull it out.
If you have any questions or comments, please send them to me at vanessa@gardenmuse.ca.
Originally published in the Creston Valley Advance on June 28, 2007.
Updated July 8, 2011.
