You’ve probably thought about including perennials in your gardens for a long time. You may even have added a few. But odds are the results weren’t what you expected. There are some perils and pitfalls you need to watch out for, and I thought this might be a good time to give you the quick tips to success. After all, it’s one of the best times to get a new perennial garden started.
The first misconception to get out of the way is that many people think they can plant perennials once and then not have to worry about them thereafter. That’s just not the case. Perennials require a lot more handwork because they’re always there (hence no rototiller and other power equipment), and they certainly require more diligent attention.
Most perennials need sun. Full sun is ideal. Most will tolerate a bit of afternoon shade. But if you’re planting in an area that’s mostly shaded, choose your types carefully, because that list is quite short.
Almost all types of perennials bloom for two or three weeks, then they go dormant for the rest of the year. Think about daffodils and daylilies that bloom in early spring and early summer respectively, or mums that bloom in the fall. When those plants finish blooming all you have is stems or old leaves and bare stubble. What that means is that you have to use a 10 or 20 types of perennials interspersed so you’ll always have something in bloom. You can also mix annuals in among them for quick bursts of color.
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If perennials bloom in the spring, you plant or transplant them in fall. That means that spring bloomers like daffodils and grape hyacinths are planted from bulbs right now. It also means that you dig, divide and relocate sweet violets, oxalis, iris, daylilies, Shasta daises, purple coneflowers and daylilies, among scores of other perennials right now so they’ll be established and ready to flower by spring.
Conversely, plants that bloom in the fall are dug and divided in the early spring. That would apply to fall asters, mums and Mexican bush salvias among others. Of course, all of these plants are also offered for sale in pots while they’re in full bloom, so if you’re getting your plants from a nursery you can plant at almost any season.
Most perennials show up best if they’re planted in clusters and clumps instead of long, narrow rows. The exception might be low, bordering flowers. The others, however, need to nestle back into shrub plantings or mingle among other perennials. Obviously you’ll want taller types toward the backs of the beds, but don’t be afraid to vary the heights within your plantings for interest.
Have a color scheme for your plantings and know the months that your various perennials will be in bloom. That’s important, because you may want that color scheme to change through the seasons. For example, you might want pinks, reds and yellows to predominate in the spring, cooling purples and lavenders in the summer, then autumnal rusts, oranges and yellows for fall. It may be difficult to pull off all of those changes, but if you’re going to try you’ll at least need to have good working knowledge of each of the plants.
Plant in raised beds of well-prepared soil. By elevating the planting beds you’ll ensure perfect drainage. You can either use some type of edging material such as river rocks, bricks or concrete edging stones to define the beds and retain the soil, or you can mound the soil, tapering it down to grade level at the edges.
Incorporate 5 or 6 inches of organic matter into the top foot of native soil. That should consist of a blend of well-rotted compost, finely ground pine bark or hardwood mulch, sphagnum peat moss and well-rotted manure. If you’re amending a heavy clay soil, also include 1 inch of expanded shade soil conditioner. Rototill all of that together with the top foot of soil and you’ll have a perfect blend that’s almost equivalent to a fine potting soil.
Give your transplants ample room to grow for several years. Most will develop into attractive clumps, and flowering will become significantly heavier their second and third years. Then, once they become somewhat congested, and especially if their blooming slows, you’ll want to dig and divide them. Rework the soil, then replant as many as you care to save at the proper spacing and give the rest to friends or discard them.
Perennials, like most of our plants, bloom best when they’re kept properly watered and nourished. Use a high-nitrogen plant food, actually the same fertilizer as you’d apply to your lawngrass, and use it at the rate of 1-2 pounds per 100 square feet of bed space every 6-8 weeks while the plants are growing actively. Use a blower on low speed to remove fertilizer granules from your perennials’ leaves after you apply it, then water it into the soil.
Mulch your plantings to slow development of weeds and also to conserve available moisture. With tree leaves coming down the next couple of months, you can use the shredded, bagged leaf clippings as a mulch or you can buy finely ground pine bark mulch to pour out around the perennials. Don’t overdo it, however. Just an inch or so will be adequate.
As your perennials finish different phases of their growing seasons in your gardens prune to remove spent flowers and seedheads. Keep it all tidy, and plug in seasonal annuals as needed to fill in the voids.