By Ray Greenstreet
Combining Perennials
For reliable beauty that returns year after year, count on perennials. You can add perennials to the landscape during any season, but spring and fall are fantastic for planting. Both seasons give plants ample time to establish roots before enduring the stressful seasons of summer and winter.
For many gardeners, determining which plants to place together is challenging. to create eye-catching combinations with little effort, focus on three key characteristics: flower or foliage color, bloom time, and plant height.
Color
Mix and match colors according to your eye. You might choose shades that complement your home’s exterior or patio furniture cushions. Or build a combination around a favorite hue. For instance, if blue is your color of choice, select plants with blossoms in shades of blue and purple. Include perennials or shrubs with foliage that has blue overtones. Monochromatic plantings always hit a homerun.
Count on white, gray, and silver to add gentle contrast in monochromatic plantings and to blend contrasting colors. For example, to subdue the clash of bright pink garden phlox with orange blanket flower, add a daisy or silver-leafed Artemisia between the pink and orange for a stunning combination.
Bloom Time
Choose plants that flower at different points in the season. Avoid buying only plants that are flowering during your trip to Greenstreet Gardens. Instead buy one perennial that’s in bloom, along with one that flowers in a different season.
Include a long-season bloomer, such as Goldsturm black-eyed susan or catmint, to savor steady color all season long. Don’t overlook fall flowers, like asters, monkshood, and garden mums.
Plant Height
Arrange perennial combinations to include plants with different heights. Stair-step plantings, from short to tall, or skirt a mid-range perennial with an ankle-high bloomer. By including plants that grow to different heights, you create a full scene that offers interest at every level.
Perennial Color Tips
- Build perennial combinations around a favorite hue, or select a color that coordinates with your outdoor furnishings.
- Use plants with white, gray, or silver blooms or leaves to soften strong color contrasts.
- When buying plants, choose ones that flower at different points in the growing season.
- Blend plants with different heights to create a scene packed with interest.
- Include a long-season bloomer, like black-eyed susan, to keep a combination lively and colorful.
Drought-Tolerant Perennials
Summer heat can cook even the hardiest perennials. Give your garden some flower power by choosing plants that open blossom after blossom—no matter how little rain falls. Drought-tolerant perennials survive annual, seasonal episodes of low to no rainfall without missing a blooming beat.
The secret to success with low water-use plants is to help them establish root systems that can find water located deep in soil. During the first growing season, deep-water drought-tolerant perennials weekly to encourage roots to strike deep in soil. Don’t water on a set schedule; check soil to make sure it’s dry. Deep watering means soaking soil 6-12 inches deep.
Mulch drought-tolerant plantings. If you select a stone mulch, realize that stones absorb sunlight and radiate heat. If foliage doesn’t blanket stones, they’ll release enough heat to shift the growing environs. This means that plants will pop out of soil earlier in spring and may even emerge during winter thaws. Cover plants with a loose, airy mulch (straw, chopped leaves, evergreen branches) after the ground freezes to protect perennials.
Drought-Tolerant Perennials
With pink blooms
Garden phlox (Phlox paniculata)
Purple coneflower (Echinacea purpurea)
Beard-tongue (Penstemon)
Autumn Joy sedum (Sedum ‘Autumn Joy’)
With blue-purple blooms
Catmint (Nepeta)
Lavender (Lavandula)
Russian sage (Perovskia)
Globe thistle (Echinops)
Stoke’s aster (Stokesia)
False indigo (Baptisia australis)
With yellow blooms
Yarrow (Achillea)
Tickseed (Coreopsis)
False sunflower (Heliopsis)
Goldenrod (Solidago)
Black-eyed susan (Rudbeckia fulgida ‘Goldsturm’)
With orange or red blooms
Blanket flower (Gaillardia)
Butterfly weed (Asclepias)
Sneezeweed (Helenium)
Red hot poker (Kniphofia)
Autumn sage (Salvia greggii)
Drought Tips
- Drought-tolerant perennials flower consistently during seasonal episodes of drought.
- Help drought-tolerant perennials establish deep roots by providing deep watering during the first growing season.
- Mulch perennials to slow water evaporation from soil
- Stone mulch absorbs sunlight and warms soil, which may cause perennials to sprout sooner in spring.
Ray Greenstreet is the owner of Greenstreet Gardens at the corner of Quaker Lane and Braddock Road in Alexandria.
