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QuickTake:
Removing about one-third of a plant's older, taller trucks each year should allow you to do the reshaping you desire.
Spring blooming shrubs are often covered with flowers before the winter rains have stopped — offering a preview of the beautiful summer season we enjoy here.
Lilacs, azaleas, forsythia, flowering quince and many other early blooming perennials need to be pruned shortly after blooming, so that next spring’s blooms can form during the summer growing season. And because our climate means things grow well here, pruning is often necessary to keep your windows clear of foliage and to keep your landscape plants at the scale you prefer.
My lilacs are starting to block the windows and are almost done blooming. One batch of them, which are 75 years old, have grown sufficiently tall that my workshop windows are now blocked. Getting at the purple blossoms requires a ladder. But they are a beautiful and fragrant part of our yard.
Another lilac wants to block a living room window and needs to be cut back almost every year. (I missed last year because ski season lasted so long.) In order to keep the shape of the plant, don’t cut off the tops of shoots.
Instead, select some full trunks — likely the tallest — and remove those after blossoms fade. Then, let a few of the small shoots coming up grow to replace the large trunks you have cut out. This will keep the form and size of the plant steady as the new shoots mature and get taller.
If you have a plant that has gotten way out of control (or a bunch of them), it may take a few years to get the plants back to the size that makes sense.
Don’t try to do a full revamp in one year. Removing about one third of the plant each year should allow you to do the reshaping you desire while not affecting the overall health of the plant.
Of course, putting the right plant in the right place will prevent a lot of window-blocking problems. How big, tall and bushy will your plant get? Are you willing to spend the time needed to keep it under control?
We are lucky to live in a mild, perfect plant-growing climate. Many commercial nurseries are located in Oregon, and Oregon plants are sent across the country and around the world.
But our mild weather conditions may require you to thwart the plants’ natural desire to grow, Grow, GROW! Or you’ll have to get used to not being able to see out the windows.