The question, “are sunflowers annuals or perennials?”, is a common point of confusion for gardeners new to growing sunflowers. Many flowers carry the name “sunflower” that are, in fact, completely different species of plants. Some sunflowers are annual and survive only one season, and others are perennials that will return every year.
All perennial and annual sunflowers produce brilliant flowers that are a highlight of any late-summer garden. So which sunflower is best suited for your location? The answer might be “a little of both!”
You’ll find that the key to identifying whether a sunflower is an annual or perennial, is to determine which sunflower you are talking about. It’s helpful to know that most of the plants that are commonly called “sunflowers” are actually related and are members of the plant genus “Helianthus”.
The genus Helianthus is native to North America, and the various species have adapted to certain regions. These species are like first cousins to each other and often have similar characteristics.
But, there are other plants that have “sunflower” in their names that are of a different genus and species.
Annual and Perennial Sunflowers
The generic name “sunflower” often first suggests the common annual sunflower, Helianthus annuus. This is the large, showy annual species that is the state flower of Kansas. Common sunflowers are a valuable source of oil and seed and are grown as an agricultural crop in many states. Acres of sunflowers in full bloom are a brilliant sight to behold!
Hybridizers have worked with annual sunflowers for years with the home gardener in mind to make varieties that astound us with their height, or shorter varieties that can be enjoyed by those with small spaces and container gardens. Flowers can be found in a variety of shades beyond the traditional golden yellow.
Whatever form they come in, common sunflowers never fail to delight us with their cheerful blooms. A single stem in a cut bouquet is sure to bring a smile. Because common sunflowers are annual, you will need to grow them from seed or buy plants at the garden center.
Jerusalem Artichoke, Wild Sunflower
Jerusalem artichoke is a perennial sunflower often grown specifically for its edible root, which is considered by many to be a healthy, starch-free substitute for potatoes. Jerusalem artichoke is native to North America and was cultivated by Indigenous peoples. The tubers are typically harvested two weeks after flowering is completed and the flavor is said to be a bit like an artichoke.
Whether planted for edible or ornamental use, Jerusalem artichoke is a plant that needs some space. In a sunny site with well-drained soil, plants can grow 6-10 feet tall with a spread from 3-5 feet. It can also become invasive, spreading by rhizomes and self-seeding. Jerusalem artichoke is a better choice for large, naturalized areas than most home landscapes. If growing as a food crop, planting in raised beds may help keep plants contained.
Showy Sunflower, Prairie Sunflower
(Helianthus x laetiflorus)
Natural cross-pollination between the rigid sunflower (Helianthus pauciflorus) and the Jerusalem artichoke (Helianthus tuberosa), resulted in the creation of the showy sunflower. The showy sunflower is a perennial that has naturalized itself, often by seed, in open fields and along the sunny edges of woodlands throughout North America and areas of Europe.
Thanks to its tall parentage, it’s not uncommon for showy sunflowers to grow as tall as 7 feet with a spread up to 3 feet. This plant makes a grand statement in a sunny border or is used as a focal point in a butterfly garden.
Cucumberleaf Sunflower, Beach Sunflower, Dune Sunflower
Cucumberleaf sunflower gets its common name from its leaves that slightly resemble those of a cucumber plant. It can be found growing wild in the dunes along the Gulf and Atlantic coasts of Florida. Also known as “beach sunflower” and “dune sunflower”, this plant is perennial in regions with mild, frost-free winters and an annual elsewhere.
Cucumberleaf sunflower has a lower stature than many other sunflowers in the Helianthus genus, but it’s still a sizable plant that reaches 2-4 feet at maturity. It’s popular for use as a groundcover for large, open areas in regions where it can be grown as a perennial.
Cucumberleaf sunflower is exceptionally tolerant of dry, infertile soils and sand. Its ability to cheerfully thrive in conditions that might cause most plants to wither makes cucumberleaf sunflower worth growing even if only as a seasonal plant. The plants produce bright yellow blooms throughout the growing season.
The giant sunflower is another member of the Helianthus genus that has an edible tuberous root (although it’s not as productive as the roots of the Jerusalem artichoke). Giant sunflower is perennial, and can be found growing wild in wetlands and boggy areas. Its mature height ranges between 4 to 10 feet, and it blooms over a long season, from early August to the first heavy frost.
The vivid yellow flowers attract many pollinators including bees and butterflies, and the seeds provide food for deer and birds. Beavers use the thick fibrous stalks to reinforce their dams. The giant sunflower is found throughout North America from Newfoundland south to Alabama, as well as throughout the Midwestern states. It is considered an endangered plant in Illinois.
The swamp sunflower is a Southern native that grows readily from the Carolinas south to Georgia and Florida. Also known as the narrow-leafed sunflower, this perennial plant has a high tolerance for salt and moist soils, making it a good choice for coastal landscapes. The wild version can reach 7 feet tall, but cultivars are bred to be shorter.
Swamp sunflowers bear bright yellow flowers that are only 2-3 inches in diameter but they’re produced in abundance and as a result offer lots of color in late summer. Helianthus angustifolius was named Wildflower of the Year in 2007 by the North Carolina Botanical Garden.
Maximilian’s sunflower is a perennial prairie native that thrives in clay soils that are high in organic matter. This plant is very drought tolerant and tends to dominate any setting in which it grows whether that’s the prairie or a home landscape. Maximillian’s sunflower can reach heights of 7-10 feet. When planted in a fertile area, where rainfall is consistent during the growing season, this sunflower can turn into a pesky weed as it readily reseeds itself around the landscape.
Maximilian’s sunflower has some allelopathic tendencies, meaning the plant releases chemicals from its roots that kill off the competition around the base of the plant. Extension offices in corn belt states warn against adding this species to native plantings.
The smallest member of the sunflower family is the western sunflower. This perennial sunflower is unique in two ways: first, it grows a mere 2 to 3 feet tall, and second, the flower stems emerge from a basal rosette of leaves. This characteristic led to its other common name, the few-leafed sunflower.
Western sunflower is a compact plant that works well in areas that receive full sun and have rocky or sandy soil. Its rhizomatous root system helps keep soils intact and reduces erosion. It is hardy from growing zones 4 through 9 and is less aggressive than most Helianthus varieties.
False Sunflower, Oxeye Sunflower
False sunflower is a bushy perennial sunflower that reaches 3 to 4 feet in height and can spread to 3 feet wide. It is often found growing in tallgrass prairies and savannahs. The most common flower color is yellow, but hybridization has introduced vivid orange and gold-orange bicolor into the mix.
The false sunflower prefers well-drained soils, but it also tolerates rocky or clay soils. It is very drought resistant once it is established in the landscape. The false sunflower is very low maintenance and produces blooms from late summer through frost. It grows well in zones 3 through 9. If you sow seeds in the garden in autumn, the plants are likely to bloom the next summer.
Mexican sunflower is a warm-season annual sunflower in every region outside of growing zones 10 and 11 (where it is considered a perennial). One of the best features of the Mexican sunflower is its tolerance for poor soil conditions. In fact, it may not perform as well in soils that are rich in organic matter, so no need to go to any extra effort to enrich your soil before planting. Mexican sunflower can also handle the heat and drought of summer like a champ.
Mexican sunflower bears flowers over a long season from midsummer through frost. The flowers are excellent for cutting, and deadheading extends its bloom time. Tithonia is a must in a hummingbird garden, as its vivid brick-orange flowers are a magnet to these creatures. It also works well in butterfly gardens.
The plants can grow from 4 to 6 feet tall, so staking may be in order, especially in windy areas. Pinching the main stem encourages side branching and keeps the height in check. This is a rangy plant with coarse, hairy leaves so it is probably best used in the back of the ornamental border or garden.
Where to Get Sunflower Plants
Gardeners seeking a showy plant that is low-maintenance, relatively pest-free, and that helps support birds, bees and butterflies, need look no further than sunflowers. Annual sunflowers are easy to start from seed and lots of varieties are available to buy in seed packets. Be sure to check the heights to find a plant sized right for your location. Many perennial sunflower species can be obtained as starter plants from the garden center. Independent garden centers are likely to carry perennial sunflower species that are best adapted to your local climate.
If you decide to grow annual sunflowers, there’s a good chance you’ll have flower heads loaded with seeds at the end of the season. If the birds and squirrels don’t beat you to them, sunflower seeds make a delicious and healthy snack for you. We’ve got simple tips on When and How to Harvest Sunflower Seeds so you can enjoy your sunflowers even after the flowers fade.