Sunday, July 15

The Well-Designed Garden
Part Two: Variety Keeps It Interesting

The most exciting gardens are always a delicate balance between two primary design principles--variety and repetition. Even though repeating the same plants throughout the landscape unifies your borders, too much repetition can make them monotonous. Choosing a variety of plants adds interest and is also a great way to emphasize certain areas of your landscape. But too much variety can be as bad, or worse, than too little. A garden with too many different kinds, colors and shapes of plants can look chaotic.

The well-designed garden is a delicate balance between variety and repetition. In this garden, trees, shrubs, containers and perennial plantings add height and interest while the colors of the plants and stonework repeat to draw your eye from end to end.

So, what's the best way to balance these two principles? By selecting flowers, shrubs and trees for the specific colors, forms and textures that they will bring to your landscape.

Most perennial plants are round. To break up the monotony, add some upright growers. Group them in one area for emphasis or repeat them at intervals in the border to carry your eye throughout the design.

Lilies are great vertical plants for sun and come in many colors and heights. Another of my favorite vertical perennials for sun is gayfeather (Liatris spicata 'Kobold'), a great 'pop-up plant' with narrow, hot-pink flower spikes on 3-foot stems. Plant them in groups of three on 1-foot spacings and repeat the groups more than once throughout your border. Gayfeather looks especially nice intermingled with prairie dropseed (Sporobolus heterolepis). (Unfortunately, rabbits and voles like gayfeather as much as I do, so repellants may be necessary.)

The vertical growth habits of blue flax (Linum perenne) and iris keep this rock garden from becoming flat and uninteresting, while their pink and blue tones help them blend into the border's overall theme.

Taller ornamental grasses make great upright backdrops. Those like feather reed grass (Calamagrostis x acutiflora), 'Heavy Metal' switchgrass (Panicum virgatum 'Heavy Metal'), or miscanthus provide both vertical foliage and interesting seed heads that look good all summer and fall. Use feather reed grass or switchgrass in groups of three or five planted on 24-inch spacings.

Purple coneflowers (Echinacea purpurea) and black-eyed Susans (Rudbeckia hirta), with their rounded flower heads, show up nicely planted in front of these vertical grasses.

Another vertical grower that provides attractive, wispy seed heads is moorgrass (Molinia caerulea ssp. arundinacea 'Skyracer'). The 6-foot tall stems look great shooting up through other perennials in the middle of the border and they have the added feature of rustling in the breeze.

Two upright perennials for the shade garden are Solomon's seal and meadow rue (Thalictrum aquilegifolium).

Solomon's seal (Polygonatum commutatum) is native to Illinois woodlands and has vertical stems 2- to 4-feet tall with attractive white flowers in May and blue-black fruit in September. Its Asian relative is variegated Solomon's seal (Polygonatum odoratum 'Variegatum'), which grows 2-feet high and has green leaves edged in white. Both these plants are well adapted to dry shade.

Columbine meadow rue has fern-like foliage and 3-foot stems that produce lavender flowers in late spring. It is not as shade tolerant as Solomon's seal, needing a few hours of dappled sunlight each day.

Not all vertical elements have to come from plant material. Fences, trellises, arbors and garden art can all lend variety and interest to your landscapes. Just remember to keep them consistent with the style and overall look of your garden and home.

Both Solomon's seal and meadow rue are great intermixed with, or used as a backdrop for, hostas. If there is adequate moisture, you can also try Chinese astilbe (Astilbe chinensis var. taquetii 'Superba') and 'The Rocket' ligularia in these areas. Both of these shade-loving perennials bear beautiful vertical flower spikes in early summer.

Perennials with colored foliage can also make your garden "pop." But remember, like cayenne pepper in chili, a little goes a long way. I always try to include some perennials with purple foliage in areas that I want to emphasize. Try purple-leafed coral bells (like Heuchera 'Plum Pudding') in groups of three or five on either side of the walk at your front door. The foliage looks great from May through November. Another purple-leafed perennial to try is 'Chocolate' snakeroot (Eupatorium rugosum 'Chocolate'). It looks great in groups of three or five behind a birdbath or other focal point. Since this plant prefers semi-shade, use it with white impatiens and red-flowered angel wing begonias for a spectacular color combination.

For sunny areas, try the purple-leafed 'Husker Red' penstemon (Penstemon digitalis 'Husker Red') at the middle of the border with 'Ruby Glow' or 'Vera Jameson' sedum in front. Save some space between these plants and supplement the border with a few purple-leafed basil plants for another touch of color.

Texture is another way to add variety to your borders. There should always be a balance between airy, fine-textured foliage and coarsely-textured, bold foliage in your garden. Bold plants are great to use as focal points because they automatically stop the eye. Use fine textured plants against a backdrop of bolder textures and forms. For example, place a larger-leafed hosta as a backdrop for a grouping of the finer-textured foliage of epimedium. Other bold perennials for the shade include bigleaf ligularia (Ligularia dentata 'Desdemona' or 'Othello') and goatsbeard (Aruncus dioicus). Bigleaf ligularia, with its wonderful large, round purplish leaves, needs constant moisture in order to do well. Goatsbeard will do better in drier shade and has 5-foot stems that bear creamy white astilbe-like flowers in June.

For sunny areas, try the bold forms of hibiscus (Hibiscus moscheutos), 'Gateway' Joe-pye weed (Eupatorium purpureum ssp. maculatum 'Gateway') and ornamental rhubarb (Rheum palmatum).

Next week
Part three: Emphasize the positive

Marcy Stewart-Pyziak teaches gardening and horticulture classes locally and at the Morton Arboretum and the Chicago Botanic Gardens. With a degree in ornamentals horticulture from the University of Illinois, this former Will County Extension horticulturist also gardens on her own 10 acres near Wilton Center.