Container gardening tips to add variety for summer
by Jo Ellen Meyers Sharp
All over the Midwest, gardeners have begun to use perennials and small shrubs in ornamental containers to perk up the summer landscape. Shrubs grown in containers add versatility.
"[They] give gardeners flexibility on where to place a plant," says Ryan McGrath, a marketing and public relations specialist at Spring Meadow Nursery Inc., in Grand Haven, Mich., a wholesale grower specializing in Proven Winners/ColorChoice shrubs. "Shrubs also add important vertical elements to container designs."
Gardeners should look for long-blooming perennials for a summer-long show, says Christine Kelleher, marketing manager for Blooms of Bressingham in Barberton, Ohio, which specializes in perennials. Tender perennials — those not winter hardy in the Midwest — are good candidates for containers because of their season-long bloom cycle, Kelleher says.
"Grasses can work well in containers, too, creating quite a dramatic element," Kelleher says. "Positioning pots of grasses of similar height could make a good screen for privacy or as a divider."
Here's a sampler of small shrubs and perennials to grow in containers:
Lo & Behold "Blue Chip" butterfly bush (Buddleia) does well in full sun and is drought tolerant. It produces blooms midsummer into fall and gets 24- to 30-inches tall and wide. It's hardy to U.S. Department of Agriculture Zone 5.
"Seward" ninebark (Physocarpus opulifolious) is marketed as Summer Wine. With wine-colored foliage and pinkish-white flowers in summer, this native shrub is very adaptable to different soil types. Its leaves turn dark red in fall, and it's hardy to Zone 3.
Limerock Dream (Coreopsis) is a tender, native perennial with a showy, long-blooming and nicely-shaped habit for pots, all summer long. It prefers full sun and will fill out large containers nicely to 18 inches tall and 24 inches wide. It's hardy to 6.
"Super Stripe" maiden grass (Miscanthus sinensis) can be planted in several containers to provide a seasonal screen or in a single container as an accent plant. It does best in full sun and will get about 4 feet tall and wide. When blooming, it reaches about 7 feet tall. It's hardy to Zone 5.
"Vienna Rawi" hydrangea (Hydrangea macrophylla), marketed as Vienna, is one of a series of dwarf plants called Cityline. It has large flowers that start out green and turn pink in alkaline soils. Plant in full sun to part shade. It gets about 1- to 3-feet tall and about 2 feet wide and is hardy to Zone 5.
In the Midwest, it can be a challenge to grow perennials and small shrubs in containers and allow them to stay outdoors all winter.
First, the container's material must be made of something that can withstand the freezing and thawing of winters in cities like St. Paul, Minn., Detroit and Cincinnati. That usually rules out terra cotta and ceramic pots. Concrete containers and fiberglass pots, however, can usually weather winter outdoors without damage.
Although many flowering shrubs will thrive in a container during the growing season, they may need to be transplanted in the ground for the winter.
A good rule is that a plant may overwinter in a container if it's one zone hardier than where it is grown. For example, a gardener in Zone 5 could safely overwinter a Zone 4 plant in a large container. However, a Zone 5 plant would need to be transplanted in the ground for the winter, McGrath says.
Sometimes known as the Hoosier Gardener, Jo Ellen Meyers Sharp lives in Indianapolis, where she manages perennials and woody plants for a large, independent garden center. A freelance writer, her work appears in many publications, including The American Gardener and Garden Gate. Sharp also speaks about gardening throughout the Midwest and is a director of the Garden Writers Association.