Although you'll have to grow annual varieties to achieve the large brown seed heads and staggering height most of us associate with sunflowers, perennial sunflowers and perennial sunflower look-alikes boast many charms. Most grow smaller both in stature and flower size than annual sunflowers, making them easier to fit into ornamental gardens. At the same time, perennial sunflowers offer autumnal cheer, sometimes providing bird seed and even human food in the bargain.
Organic garden author Toby Hemenway prizes Helianthus maximilianii as a multipurpose plant. He uses groups of these fuzzy-stemmed sunflowers to form a living hedge that blocks deer from entering garden spaces planted with vulnerable crops. "In winter, I trim the stalks to about 4 feet high, and the deer really hate the stiff spikes that remain," Hemenway reports in his book "Gaia's Garden." The spring shoots are edible, and its seed heads attract birds. Prunings of the perennial sunflower also add bulk to the compost pile. Maximilian sunflower grows 7 feet tall and bears 4-inch yellow flowers in late fall.
Jerusalem artichokes are neither artichokes nor from Jerusalem. Instead, these members of the sunflower family are native to North America. Not only do Helianthus tuberosus bring carefree, perennial cheer to the yard, but this ornamental flower is also a food crop. The perennial sunflower bears edible tubers that Purdue University likens to water chestnuts. Depending on the cultivar, Jerusalem artichokes grow from 3 to 12 feet high. Gardeners in high-wind areas may find the dwarf cultivars useful, but staking will help the common Jerusalem artichoke.
A multi-headed sunflower, the Jerusalem artichoke bursts into bloom in late summer. The small yellow flowers range from 1 ½ to 3 inches in diameter. Harvest the tubers in the fall, making sure to leave behind a few tuber pieces per plant to ensure the flowers regrow and continue to produce edible crops in coming years. If grown in great quantities, Jerusalem artichokes also can be used for cattle forage, ethanol and a corn syrup-like product, according to Purdue University.
Common Perennial Sunflower
Hardy to zone 4, Helianthus multiflorus blooms through most of the summer. Washington State University likens its double-petals blossoms to yellow chrysanthemums. Perennial sunflower grows 5 feet tall and almost as wide. Unlike many sunflowers, Helianthus multiflorus can take partial shade. The plant also tolerates drought. Deadhead the blooms regularly for continual bloom and divide the clumps every few years.
Additional Perennial Sunflowers and Sunflower Look-alikes
Other perennial members of the sunflower family include swamp sunflower (Helianthus angustifolius), a tall member of the perennial group with small flowers and a preference for moist soil. Helen's flower (Helenium autumnale) features yellow, pie-wedge-shaped petals and is more compact than other sunflowers. Ten-petaled sunflower (Helianthus decapetalus), a small plant, prefers sandy soil. Woodland sunflower (Helianthus divaricatus) tolerates shady conditions. False sunflower (Heliopsis scabra), as the name suggests, looks like a sunflower but grows to only 3 feet tall. It likes sun or part shade and moist soil.