Designing with Perennials

May 10, 2012

5 Important Tips for a Knockout Perennial Garden

It’s the gardener’s million-dollar question. How do I get a knockout perennial garden with waves of color spring, summer, and fall? And, I want a showcase that won’t cost me a lot of money or maintenance time. No problem! You’ll find the ‘Ever-Blooming Garden in a Box’ in aisle three. Keep dreamin’!

For over a decade I have helped frustrated homeowners realize this dream. I help them wake-up and smell the roses…literally!

Here are some simple steps for creating Monet’s garden in your own backyard…

Use restraint

When the first stretch of warm weather hits our area, it triggers a plant buying frenzy at garden centers. Many gardeners lose all self control and grab anything that is in bloom. Overloaded shopping carts filled with colorful flowers wheel up to cash registers. The catch? Now you have a garden that is frontloaded with spring color but lacks later season interest. Like a runner, you went out too fast and didn’t pace yourself. To protect yourself from binging on spring bloomers, go to the garden center with a pre-planned list that includes summer and fall bloomers.

Enjoy a virtual shopping spree while creating a seasonal plant list tailored to your garden’s site

Get a piece of paper and divide it into three columns. Label one column for spring bloomers; one for summer; and one for fall. Now let your fingers do the walking. Flip through the pages of a great gardening book like The Flower Gardener’s Bible by Lewis or The Ultimate Flower Gardener’s Top Ten Lists by Kerry Ann Mendez and write down the names of the plants you love. But before writing them in the appropriate column based on their bloom time, make sure they fit your garden’s light condition (sun, part sun, part shade, shade) and hardiness zone (most gardens in the Capital region are zone 4 or 5). Also include the plant’s height in your notes. Many folks also find it helpful to cut out the plant’s photograph and paste it in the column.

Stack the odds for remarkable color by planting ‘two column’ perennials or flowering shrubs that bloom for six weeks or longer. These workhorses cover more than one season, providing a ‘greater return’ for their share of real estate. Great investments include perennial Geranium ‘Rozanne’; Fleeceflower ‘Firetail’; masterwort (Astrantia); repeat blooming daylilies such as ‘Sunday Gloves’, ‘Custard Candy’, and ‘South Seas’; coneflowers (walk on the wild side with some of the newer introductions such as ‘Sunrise’, ‘Fatal Attraction’, and ‘Virgin’); dianthus ‘Frosty Fire’; Hydrangea ‘Endless Summer’; and knockout roses.

Incorporating striking foliage plants is another design trick for enchanting gardens

Leaves are there before, during and after blooms and anchor great perennial gardens. When folks attend my monthly open gardens, almost half of the “What is that plant” questions are directed at bloomless perennials. That is not to say they don’t bloom at some point, it is just that their leaves are dazzling. Flowers are just the icing on the cake. Some fetching foliage plants include coral bells ‘Marmalade’, Key Lime Pie’, and ‘Green Spice’; Ligularia ‘Britt Marie Crawford’; Heliopsis ‘Lorraine Sunshine’; Brunnera ‘Jack Frost’; Sedum ‘Purple Emperor’ and ‘Samuel Oliphant’; and Heucherella ‘Spotlight’. Need I say hostas and ornamental grasses?

Well placed annuals can always carry the show when perennials and woodies are taking a breather

Since I am a fanatical, low-maintenance gardener, I will only mention annuals that require no deadheading and require less water. Some of my favorites for sunnier spots are verbena; million bells; browallia; wave or supertunias; Mandalay begonias; vinca; and zinnia ‘Profusion’. Those for shadier spots include coleus, New Guinea impatiens and torenia. Browallia and Mandalay begonias will also do well in lower light.

Pleasing, ‘eye-candy’ gardens are the result of planting multiples of the same plants versus the ‘gum drop’ look. Gum drop gardens feature one of everything from the plant buffet table. This can cause dizziness, or worse yet, nausea to an unsuspecting onlooker. Plant in groups of threes, fives, sevens, …you get the gist. This doesn’t mean you cannot have single specimens of plants or even numbered groupings. Just don’t do so with abandon. Place plants off-center from each other when digging them in. Think triangles and zig-zags, not straight lines.

Repetition is another key to beautiful gardens

Incorporate the same plants at various intervals through the garden. Flowers don’t necessarily have to be the same color but as long as they’re in the same (genus) family and look similar. Don’t assume all genus cultivars look the same; as with people, sometimes the differences are striking. Lychnis chalcedonica (Maltese Cross) and Lychnis coronaria (Rose Campion) are good examples. Also, when repeating plant groups in the garden, try to site them at different depths in the bed. Pull some forward and place others farther back. This looks more natural.

To calculate the number of perennials to purchase for an area, most shorter varieties are spaced 12” or less apart; medium size plants need 12” – 18”of ‘personal space’; and larger perennials require 2’ or more. Refer to the plant tag for recommended spacing. And remember, when the tag states 18”, it is talking to you, not your neighbor. The tendency is for gardeners to jam perennials closer together than instructed because we want a full look right away. This backfires for several reasons. You will need to divide the plants sooner (more work and time on your part) and the plant’s roots compete for nutrients and water, resulting in less voluptuous blooms.

With these tips in your garden apron, you should feel empowered to give your flower beds a face lift so they’ll glow April through November.