Is There a Perennial Sunflower?
Flowers in the Helianthus genus number about 50 and include annuals, those large, sunny yellow blooms you mostly see in gardens. They also include Helianthus perennial sunflower varieties. Perennial sunflower plants actually make up the majority of sunflower varieties native to North America. Most of the popular garden varieties that you see are annuals, but you can get a lot more range of size and even color when you look into perennial sunflowers. One easy way to tell the difference between an annual and perennial sunflower is in the roots. Annuals have small, stringy roots while perennial sunflower plants grow tubers.
Perennial Sunflower Varieties
The flowers of perennials are not as large and striking as annuals, but they still have a lot to offer:
Ashy sunflower (Helianthus mollis): Ashy sunflower grows tall and vigorously, producing bright yellow, 3 inch (8 cm.) flowers. It can be invasive but looks great as part of a wildflower meadow.
Western sunflower (H. occidentals): This species, known as western sunflower, is shorter than many others and may be more suitable for a home garden. It is also less invasive and easier to contain. The flowers are 2 inches (5 cm.) across and daisy like.
Silverleaf sunflower (H. argophyllus): Silverleaf sunflower is tall, 5 to 6 feet (1.5-2 m.) and is known for its silvery leaves. Soft and covered with silky fuzz, the leaves are popular in flower arrangements.
Swamp sunflower (H. angustifolius): Swamp sunflower is a pretty and tall sunflower that tolerates poor soil and salt.
Thin-leaved sunflower (Helianthus x multiflorus): There are several cultivars of this cross between the annual sunflower and a perennial known as thin-leaved sunflower. ‘Capenoch Star’ grows to 4 feet (1 m.) and has bright yellow flowers. ‘Loddon Gold’ grows up to 6 feet (2 m.) and has double blooms.
Beach sunflower (Helianthus debilis): Also called cucumberleaf sunflower and East Coast dune sunflower. This spreading sunflower perennial works well in coastal gardens, as it’s salt tolerant and thrives in sandy conditions.
Perennial Sunflower Care
Perennial sunflowers are great additions to native gardens but be aware that they can spread pretty rapidly. You’ll need to control where they grow if you don’t want them taking over too much space. Most types of sunflower prefer rich, fertile soil, although they can tolerate poorer soils too. The ground should drain well, but the flowers need regular watering or rain and do not tolerate drought well. Plant all varieties in full sun. It can be difficult to find seeds for perennial sunflowers, but they are easy to grow from seed or from divisions. You should divide your perennials every two to three years and space them 2 to 3 feet (61-91 cm.) from each other, so they have room to grow and spread. Maintenance for perennial sunflowers is pretty low. Stake some of the taller varieties to keep them upright and trim the plants back in the spring. Use fertilizer only if your soil is poor.
