Twenty years ago, I began creating a long flower border against an old stone wall that ran along the west side of our 1760s Cape Cod-style house. Big skies, expansive views, and lots of sun make it the perfect place for a long bed full of perennials. Over time I widened the border, adding shrubs and small trees for year-round interest and a diverse assortment of annuals and tropicals to broaden the color palette and intensify the late-season show. mixed But as some of the fast-growing trees matured, they began to dominate, and several shrubs began to take up too much space. Looking towards the border, the eye was no longer drawn to the beautiful views of the distant hills but to the enclosed lawns inland. I was feeling cramped and needed to find ways to open up the space and get more sun into the garden.
It was a tough decision, but last spring I cut back some of the larger trees in hopes of getting my full sun border back and bringing the planting back to scale. Although each tree left a large hole, I knew the existing sun-loving perennials and shrubs would fill in over time. In the meantime I plan to fill the gap with annuals that grow tall and wide, such as flowering tobacco (Nicotiana sylvestrisannual) and ‘Amisted’ sage (Salvia ‘Amistad’, zones 9–11). I plan to add some more shrubs for structure and easy maintenance.
Design Strategy 1: Remove plants that outgrow their welcome.
|Trees were removed.
The first tree to go was Sunburst.® honeylocust This chartreuse was a beautiful new growth tree that worked well with my colorful and somewhat tropical looking border. It did not drop dirty leaves, and its visible canopy provided filtered shade that was tolerated by many nearby plants. Unfortunately, it ended up being bigger than I expected and ended up blocking the view behind it. Its height was out of proportion to the rest of the frontier, and it still had more to grow.
I also took down two ‘Degroot’s Spire’ arborvitaes that looked great in their middle years but eventually got too tall. Although I was disappointed to see them go, I was also relieved to wrap them each winter and spray them with deer repellant every three weeks year-round. Last up was the ‘Yellow Lantern’ magnolia, which had grown to 30 feet tall and wide. In an excited moment a few days before hosting my son’s wedding, we cut it and then rejoiced as the beautiful view unfolded and the sunset shone seamlessly across the border across the lawn.
I left the honey locust and magnolia stumps, planning to turn them into cut bushes. By early September, five months after its bite, the honey locust had grown about 4 feet of new growth. Now I can cut new branches every few years to keep it the height I want. Magnolia stumps can also push new growth, with beautiful large leaves that will contrast well with smaller perennials nearby.
Design Strategy 2: For some shrubs, a cutback may be in order.
|The bushes are cut back.
Another tactic to keep a mixed bed from getting too crowded is mulching. For some trees and shrubs, an early spring cutback not only keeps them indoors, but it also pushes them to produce larger, more colorful plants. The three smoke bushes I cut are particularly good examples of this: ‘Grace’, ‘Golden Spirit’, and ‘Royal Purple’ (Kotense Kogegria ‘Royal Purple’, zones 4-8).
yellow catalpa (Catalpa ovata, zones 4–8) can grow to 30 feet tall and wide, but with severe cutting each spring it produces large, yellow leaves on a bushy form that grows to about 8 feet tall and wide. Similarly, an annual cutback of a princess tree encourages the growth of abundant, tropical-looking green leaves on stems that reach 12 feet tall. The leaves look great in the border with the larger annuals and tropicals I like to include.
This spring I also cut back an over-mature tiger-eyes smack that had started to spread across the lawn. It regenerated beautifully, but I’ve noticed some sumac shoots coming up nearby. If it becomes a problem, I may have to remove the bush entirely.
A surprising number of shrubs will undergo severe pruning each year. Don’t be afraid to grab the loopers; The result will often be a better looking bed.
Design Strategy 3: Plan a garden with slow-growing plants, and then plan for change.
|The lazy farmer
When you plant a border that includes trees, consider dwarf varieties or small specimens of slow-growing cultivars that will take years to outgrow their places. As these trees mature, you may decide to replace the sun-loving perennials in the lower area with more shade-tolerant varieties. Or you can choose tall trees with open branch patterns, thin trunks and tall canopies that are less likely to shade other plants or interfere with sight lines.
Ideally, you can predict how the plants will grow and how your garden will develop over time, but this is very difficult. To be honest, I love making changes and I’ve found from experience that plants will regenerate much faster after a big change than you might imagine. Try not to get too attached to a particular plant or idea. At the end of each year, ask yourself if any of the basic building blocks of your garden could be replaced. Would cutting back do any good? Would it excite you to make a fresh start in an area of the garden?
Subtraction can be the most difficult design change, but it can also be the most effective. Negative space helps open up views of more distant trees and sky. I will miss the winter structures of the trees I removed and the sense of permanence they provided. But at the same time, I’m excited about all the possibilities that the return of full sun will bring to my long border.
princess tree (Paulownia tomentosa)
This plant is considered invasive in AL, CT, GA, IN, KY, ME, PA, SC, TN, VA, WI, and WV.
Japanese Aralia (Aralia Elata.)
This plant is considered invasive in MD, NH, NJ, NY, and PA.
See invasiveplantatlas.org For more information.
Laura Trowbridge is a garden designer based in Peterborough, New Hampshire.
Photos and illustrations: Carol Collins