Less Will Mean More: The Careful Art of Pruning
During that long break between storms, I had a chance to visit some gardens and found that gardeners are all doing the same thing right now--cutting back.
On garbage day, trash cans are full of thorny rose canes and the bare branches from fruit trees. Compost piles are getting taller and taller, threatening to go over the fence, as prunings from perennials and shrubs get tossed on top.
I just finished tidying up my garden, cutting back things and pruning the roses, filling my green can with wicked branches.
As usual I spent a lot of time simply staring at the unpruned rose plants, planning my attack and, afterward, staring again because I’m never sure I did it quite right. We have all sorts of roses--from a low white ground-cover rose that I’m trying out to arching Austin roses and sprawling oldtimers like ‘Ballerina,’ and each requires its own kind of pruning as each grows in its own eccentric way.
I let the old rules--”leave nothing thinner than a pencil, remove crossing or rubbing branches”--be my guide. Then I thin a little more, taking out whole canes until the plants look light and airy and there is room for new growth.
Height has nothing to do with how I prune, because some of the roses are huge and some are quite short. None looks like the drawings in articles and books.
Next I move onto the other plants, getting them tidied up for spring. There are few rules governing this job, particularly when it comes to the perennials or the soft little shrubs called herbs, shrubby perennials or “sub-shrubs” by the botanists.
A Good Question
I recently received a query on this subject from a gardener in Venice. She wrote, “I can find plenty of info on perennials that require division for refreshing, but how do I treat Nepeta, as it looks so shaggy right now?” She added: “How about santolinas, helichrysum and artemisia?”
It’s a good question because all of these popular plants are sold as perennials but don’t die back like the herbaceous perennials described in books, yet they need some kind of winter pruning.
Of these, catmint (Nepeta) gets the scraggliest, and I have often wondered myself what to do with the tangled catmints in my garden.
According to Mary Lou Heard at Heard’s Country Gardens in Westminster, a nursery that specializes in perennials, you can simply cut it back to within an inch of the ground and it will come back fresh as a daisy.
Heard carefully thins it a little every few months to keep it neat, but once a year, in winter, she cuts it close to the ground. She just cut hers back about a week ago, and I’m about to give her advice a try.
Santolinas are another story. If you cut into the bare, woody growth below the leaves, they will probably not recover. They certainly will never look the same and will probably die.
The solution is to lightly prune santolinas throughout the year so they never get too scruffy. You can try cutting back overgrown santolinas, but it is probably better to replace the plants with new ones and start over. In my own garden, I’ve had to do this every five years or so.
Artemisias are tougher plants and, according to Heard, you can cut them back to foot-tall bushes and they’ll most likely bounce back, though I’ve never had the guts to try. Maybe this winter.
In cases like this, when you’re not sure how a plant will respond to cutting back, you can try a technique suggested by Heard. She lightly prunes back the plant in fall, then lets it go through winter. In early spring you should be able to see if it is sprouting near the base. If so, you can safely cut it back to those sprouts; if not, better leave well enough alone.
The Cautious Tack
I just did this with a commonplace Santa Barbara daisy. It was one of the larger-flowered cultivars and very overgrown, sprawling everywhere. I cut it into a tidy little bush shape in late fall, but already I’ve seen that there are far more sprouts at ground level than on the cut stems--so I cut it back all the way.
Now it looks much neater, and I can see that it will make a much tidier, and fuller, plant in the spring.
Helichrysums--and I assume our questioning reader is talking about the chartreuse ‘Limelight’ that has been so popular these last few years--are tricky. Sneeze on them and the whole plant falls apart, or so it seems--the stems unraveling like a ball of soft yellow-green yarn.
This plant is tough and beautiful until you try to prune it. Never whack them back; just prune the tips constantly so they don’t get too big or lanky. Whacking it back will destroy the look of the plant.
In tight quarters, the plant must be replaced eventually (they last three to five years, longer if they have room to spread eight feet or so). Never try to pull off dead stems. They must be cut.
The other helichrysum, commonly called licorice plant, is more like santolina: You can prune it lightly but not hard, or it will never recover properly.
There are few hard and fast rules for cutting back plants, with even roses being a bit confusing now that there are so many kinds on the market.
But careful observation will generally teach you how to prune and cut back and, at worst, you’ll have some great stories to share with other gardeners--like the time I got trapped pruning a climbing rose up on the roof until my kids came home and rescued me from the thorns.
