by Gardening Coach Susan Harris
Lots of homeowners are looking for evergreen shrubs to cover up the foundation of their house, or to create screening and privacy from their neighbors. That may be why cherry laurel (Prunus laurocerasus) is so popular with landscapers, whose job it is to find plants that do all that reliably, and why I recommend it so often myself. It even comes in a choice of heights for seemingly every situation and given good light, they grow pretty fast. Their white blooms in springtime are fragrant. They’re what you might call do-ers – plants that perform well in the garden for many years.
The ‘Otto Luyken’ variety grows to 3-4 feet tall and 6-8 feet wide and as you can see in this photo of my house, it’s short enough to not block first-floor windows. Another popular choice is ‘Schipkaensis’ or ‘Schip’ , which reaches 4-5 feet tall and 5-8 feet wide. There are lots more varieties that reach from 10 to 20 feet, like the very old hedge in the next photos that runs along the side of my back yard.
Renewal pruning is counter-intuitive
First I have to confess to pruning my cherry-laurel hedge all wrong for its first 15 or so years. When it got taller and wider than I wanted it to be, I started shearing it across the top and the sides, and after years of that treatment the shrubs gradually became leggier and infested with pests of all sorts. My pruning technique had created an encasement around each plant that kept air, light and water from entering – all enticements to disease. And aesthetically, the shrubs no longer had the fullness and natural shape that was the point of planting them in the first place. And by the time I realized all this, the hedge was full-grown and not something I could easily replace even if I wanted to.
So I started attending pruning lectures (including one excellent talk by our own Gene Sumi) and reading books on the subject, and proceeded to begin the process of renewal and renovation that’s brought them back to health and allowed them to be their prettiest, too. This technique can (and should!) be used on dozens of old and overgrown shrubs that are commonly seen in the garden that really could look so much better with just a bit of effort. Some that come to mind are azaleas, viburnums, forsythia, mock oranges, and forsythias, all of which can be pruning now through the end of June. Spireas also benefit from renewal pruning and the early bloomers are ready for the pruners now; late bloomers like ‘Anthony Waterer’ will be ready in a week or so.
So here’s how to renew these old, overgrown and often misshapen shrubs. Each year for three years, simply remove one third of all the stems down to their origin (yes, close to the ground). I call this counter-intuitive because really, who’d ever imagine doing it? And when I suggest this to clients, disbelief is written all over their faces. I usually make the first cut myself just to demonstrate how easy it is to remove large stems and how immediate the reduction in crowding. My hedge here grew back and achieved the height and shape I was after in about five years. Gardening sure teaches patience, doesn’t it?
Now to touch briefly on azaleas – because they’re even more common in our region and even more likely to be old and overgrown. When I bought my lot it included some 8-foot-tall azaleas that had strained to get more sun for years and become quite leggy. This same renewal pruning technique worked just as well for them and they’re now round, full and healthier than ever.
So how do you keep these shrubs pruned for good health and beauty? Once they’re full-grown or close to it, all of them benefit from a quick annual pruning that includes:
- Removing all dead, dying and diseases branches and stems – back to where they start. (Never cut just anywhere, leaving a stump. Cut a half inch above a branch.)
- Removing at least one of the oldest stems back to the ground or close to it. This is often the tallest of the stems, and almost always the thickest and showing age in color – usually grayer.
That’s it. I also regularly remove stems that are lying on the ground, often called “limbing up”. Too much limbing up can ruin the natural shape of the plant, so I remove just the limbs that are smothering groundcovers and hiding weeds, especially those viney weeds that can totally enshroud the poor plant before you know it.