Above: Nigella, or love-in-a-mist, graces the spring and early summer garden with subtle shades of blue, pink or white flowers.
Left: Rudbeckia hirta ‘Indian Summer’
Gardeners like plants that are easy to grow and those that multiply without a lot of effort, especially if they have a lot of ground to cover.
Some perennials and annuals self-sow, casting their seeds to the wind to root some place else in the landscape. These can be transplanted to desirable locations or shared with others. Neatnik gardeners may be less enthused about self-sowing plants, so be selective about which ones you introduce to the landscape.
Some shrubs spread by suckering, sending up stems to form what’s called a colony. Winterberry holly is an example. Still others sprout new plants from branches that root where they touch the ground, a process called layering. Hydrangeas are very easy to propagate this way.
Here’s a sampler of plants that keep on giving:
Love-in-a-mist (Nigella damascena) has blue, pink or white flowers and fine, ferny foliage in spring and early summer. It does best in full sun, but tolerates light shade. It gets about 12 inches tall. Nigella makes a lovely cut flower and the seeds are edible.
Chinese forget-me-not (Cynoglossum amabile) has tiny blue flowers in spring and early summer. It does best in full sun to part shade and makes a good companion for spring-blooming bulbs. If given adequate moisture, it will produce flowers off and on through summer. It can be used as a cut flower. Don’t confuse this annual with the perennials Myosotis sylvatica or Brunnera sp., which also are called forget-me-nots.
Gloriosa daisy (Rudbeckia hirta) comes in lots of colors, from orange and yellow to red. This native plant does best in full sun and well-drained, average soil. Gloriosa daisy is a great cut flower. The seed heads also are a source of food for birds. Some rudbeckias are perennial or biennial.
Far Left: Purple coneflower
Left and Above Middle: The native columbine blends nicely with ‘May Night’ salvia and a Knock out ™ Red rose in late spring.
Right: False sunflower
Purple coneflower (Echinacea purpurea) readily scatters seeds throughout the garden to create new plants. This native plant does best in full sun to light shade in average, well-drained soil. It gets about 2 feet tall and is a long-lasting cut flower. The dark brown seed heads are attractive in the winter landscape and they serve as a food source for finches all year. Hummingbirds visit this plant in summer.
Columbine (Aquilegia canadensis) is a short-lived perennial that makes up for its fast life by sowing its seeds throughout the garden. This is another native plant that is almost evergreen, frequently holding on to its green foliage through the winter. It does best in full sun to part shade in average soil. There are several hybrids, such as the McKana series, which also self-sow a bit. Columbine is a beautiful cut flower. Hummingbirds like it, too.
False sunflower (Heliopsis helianthoides), sometimes called ox-eye daisy, gets up to 5 feet tall with great branching characteristics, which produce many yellow daisy-like flowers that are great for cutting. A native plant, it does best in full sun and average soil.
Left: ‘Winter Red’ is a cultivar of a native holly introduced by Simpson Nursery in Vincennes, Ind., in 1977. Middle: Ilex verticillata‘ Jim Dandy’ Right: ‘Brilliantissima’ is a red chokeberry that spreads by suckers to offer four seasons of interest.
Shrubs that Colonize
Winterberry holly (Ilex verticillata) is dioecious, which means it needs a male and female plant to produce berries. And it’s the bright red berries in winter that make this shrub worthy of a spot in the medium to large garden. This native plant does best in average soil that is a bit on the wet side in full sun to part shade. If it’s happy, the species will get up to 9 feet tall and will colonize to cover a 10-foot area. This is a deciduous holly, so it drops its leaves in fall. There are many cultivars worthy of smaller gardens, including the female ‘Winter Red’ and male ‘Southern Gentleman’, which were introduced by Robert Simpson of Simpson Nursery in Vincennes, Ind. Winterberry holly is a food source for birds in winter, but the berries are poisonous for humans. It has great fall color and small, insignificant flowers in early summer.
Chokeberry (Aronia sp.) comes in black (A. melanocarpa) and red (A. arbutifolia) and will spread by suckers or self-sowing. The native species gets about 8 feet tall and wide. It adapts to wet or dry areas in full sun to part shade. ‘Autumn Magic’, ‘Morton’ and ‘Viking’ are good black chokeberry cultivars. ‘Brilliantissima’ is a nice red one. Although these suckering shrubs produce showy berries, the fruit is at the bottom of the menu for birds. They will eat the berries only after the fruits have gone through several freezes and thaws. Chokeberry has small flowers in early summer and beautiful fall color. (Some sources might list this plant under its new botanical names: Photinia pyrifolia for the red and P. melanocarpa for the black.)
Layering is simple to do.
Shrubs for Layering
The easiest way to propagate some shrubs is by soil layering. Here’s how:
• In spring, select a flexible branch that will bend to the ground.
• Remove all side branches from the branch.
• About 12 inches from the tip of the branch, make a slanted cut on the under side.
• Make a slight depression in the soil where the cut side of the branch touches the ground. Fill the depression with high quality potting mix or rich organic matter. The cutis where the roots will form.
• Anchor the branch to the soil with lawn staples, bent wire or a stone.
• Apply a mound of soil about 1 inch deep and 6 inches long on top of the branch at the cut area.
• The cut section of the branch should root in eight to 10 weeks. Tug gently on the branch to see if it has rooted. There also might be new growth, which is the surest sign of a well-rooted branch.
• With a spade, snips or other tool, sever the new branch between the mother shrub and the newly formed rooted portion.
• Transplant to the shrub’s new location.
A version of this article appeared in a May/June 2011 print edition of State-by-State Gardening Magazine.
Photography courtesy of Ron Capek, John Herbst, All-America Selections, Jo Ellen Meyers Sharp, The Ladybird Johnson Wildflower Center, and Bailey Nurseries. Illustration courtesy of Gardening Techniques, Alan Titchmarch.