Late Summer Blooming Perennials for Zone 3

Full Sun

• Late-summer flowering perennials in full-sun sites glow as summer draws to a close. Threadleaf coreopsis (Coreopsis verticillata "Grandiflora") bears 1- to 2-inch-wide, yellow, daisylike blooms above clumps of feathery foliage. Suitable for USDA zones 3 through 9, this perennial grows 2 to 3 feet tall and wide. Small globe thistle (Echinops ritro "Veitch's Blue") provides an interesting contrast, with blue pompom flowers at the tops of tall stems. Hardy in USDA zones 3 through 8, it grows 3 to 3 1/2 feet tall and 1 1/2 to 2 feet wide. Both plants bloom from June through September.

Shade

• When sheltering from hot, late-summer sun, you can still enjoy blooms that thrive in shady areas. Bugbane "Brunette" (Actaea simplex "Brunette"), hardy in USDA zones 3 through 8, bears spikes of fluffy white flowers during August and September. Tolerating both full- and partial-shade sites, it grows 3 to 4 feet tall and 2 to 3 feet wide. White wood aster "Eastern Star" (Eurybia divaricata "Eastern Star") also bears, above mahogany foliage, white late-summer flowers to brighten shady spots. Also suitable for USDA zones 3 through 8, it grows 1 to 1 1/2 feet tall and wide.

Wet

• Wet sites are suitable for late-summer flowers that are drought intolerant. Two wet-site perennials hardy in USDA zones 3 through 8 are lobelia "Purple Towers" (Lobelia "Purple Towers"), bearing unusual, two-lipped dark purple blooms on 4- to 5-foot stalks from July to September, and "Zimbelstern" sneezeweed (Helenium "Zimbelstern"), which provides bright yellow, daisylike blooms from August to October. Lobelia "Purple Towers" tolerates full-sun and partial-shade sites, though it needs some protection from midday heat in southern and midwestern states. "Zimbelstern" sneezeweed needs a full-sun site -- six or more hours of sun a day.

Dry

• Flowering perennials for dry sites suit gardeners with little time for watering. Purple coneflower (Echinacea purpurea) flowers from midsummer to early fall, bearing copper-centered, rose-purple blooms. Suitable for USDA zones 3 through 9, it is drought tolerant and grows 3 to 6 feet tall and 1 to 3 feet wide. Yarrow (Achillea "Moonshine") bears yellow flower heads on 18-inch stalks through late summer. Growing 1 to 3 feet tall and wide, this perennial is hardy in USDA zones 3 through 8.

After Summer

• Proper care when winter starts to set in can help many of late-flowering perennials return for another season. After plant foliage has been killed by the first few frosts, cut plants down to 3 inches above the ground and remove all dead growth. Spread 3 inches of mulch, such as garden compost. As plants begin to grow again in spring, remove the mulch to allow spring rains to soak the soil.