Of all the plants that gardeners grow, perennials are the backbone of our gardens. These long-lived plants – they go dormant in the winter but return bigger and better in the spring – come in every shape, size, color and texture. As we plan a landscape, perennials are the choice to fill in lower and mid layers with form, color and texture. A foundation planting with a base of shrubs can take on a new life when perennials are added. An English “cottage garden” often includes a small tree or woody shrub for structure, but these romantic gardens are almost all perennials. In big yards, use large sweeps of hostas, coral bells and ferns under trees. This technique is called “massing” and can cover a lot of otherwise plain ground.
By planning a simple design using a complementary color scheme, varying leaf textures, and staggered bloom times, you can have beautiful perennial border throughout the growing season. Perennial borders are a great way to attract birds and beneficial insects. For example, the monarch butterfly depends on milkweed – and milkweed is a lovely perennial, at home in any border.
First, know the growing conditions for the area in which you want to plant. A perennial requiring full sun and well-drained soil will languish in a shady or boggy site, so plan accordingly. Conversely, a plant that prefers shade will appear washed out and stunted when grown in full sun. Choose plants that are suitable to your climate. A perennial that’s hardy in Zone 9 may die in our Zone 7, so do your homework first and make sure the plants are suited for the region or even microclimate. If you’re unsure, talk to the staff at a nursery; I know my staff will be happy to assist you with appropriate choices and varieties for your site.
Know your space. Perennials can grow into good-size plants – like baptisia and ornamental grasses – and some spread, covering a lot of ground in just a couple of years. Give the plants room to grow and they will flourish.
As you lay out the garden, plan for the tallest plants and flowers to go toward the back of the border or center of an island bed. Then plant out from there, layering down, so that the shortest plants are in the front. The best landscape designs use this technique. It allows the garden to appear full, while showing off as many plants as possible.
For a sunny perennial border, plant tall growers like Joe-Pye weed, garden phlox, andmonarda in the back. Coneflower, iris, salvia, gallardia, and veronica are good mid-level growers. Down in front choose shorties like dianthus, creeping verbena, and cranesbill.
Design a shade garden by placing large, thick-foliage plants like hosta just behind the finer foliage of astilbe or ferns. Add a pop of color with coral bells; they range in foliage color from chartreuse to deep plum.
Don’t forget ornamental grasses. They provide great texture, winter interest and their fall “flowers” come out when just about everything else is shutting down for the year. It’s fun to experiment with different combinations to incorporate all three design elements. You’ll be a better gardener for it.
Although perennials are beautiful when in flower and can make for a stunning display, the blooms usually last for a few weeks. So plan the design around form, texture and color of the foliage. The best-looking designs incorporate diversity, and this is where form and texture really come into play. When perennials are in full bloom, who notices the foliage? But, for the 80 percent of the time that we see the plants not in bloom, all we can see is foliage.
Our nursery staff offers a tip to newbie gardeners. When planning a perennial border, shop at the nursery four times that first year: Spring, early summer, mid-summer and early fall. The temptation is to hit the nursery in spring and fill your cart with all those beautiful spring flowers. But once those plants have finished blooming, the border will lack flowers. Keep in mind what is in bloom in the nursery will be blooming in your garden. Choose your plants over the course of a couple of months, and you’ll end up with an all-season garden.
Perennials are hardy and good natured plants. If you don’t like where you put a plant, you can easily move it to a new location. And most gardeners will admit that they move plants around every year, trying out new combinations and making room for “just one more” that they “can’t live without.” A garden is, after all, almost always a work in progress.