Fall-Blooming Perennials: Perennial Sunflower

You are probably thinking right about now that I have lost my mind when I call sunflowers a fall-blooming perennial, but I am not talking about the annual sunflower (Helianthus annuus) that bloom in the summer. This perennial sunflower (Helianthus spp.) is a different type of plant -- and one that can give you some great blooms late in the season.

The perennial sunflower has smaller blooms than its annual cousin. In fact, they are rather daisy-like in appearance and about 2-3 inches in a bright yellow that appear in late summer and last into the fall. (You might have even seen some varieties of these and thought they were a solid-yellow rudbeckia.) Depending upon the species, these sunflowers can grow to be from 4-feet-tall to as large as 10-feet. They do not grow on one sturdy stalk as do annual sunflowers. Instead, most have a bushier appearance. Not only is this sunflower great for the fall garden, it makes a wonderful cut flower as well. Most varieties are hardy in Zones 3-9 and will do well in almost any type of soil; although, they prefer a moist, fertile, well-drained soil. They will grow, however, in average soil and even clay. (Mine do not seem to care at all about the type of soil in which they may find themselves as long as they are watered regularly.) Grow in full sun or, in more southern climates, partial shade. (While perennial sunflowers usually do not require staking, those grown in partial shade can get a bit floppy, which means that you will probably want to go ahead and stake them.) If you want to encourage more profuse blooming, feed them some bloodmeal or add additional compost. They will probably need to be divided about every 3-4 years. You can also propagate by taking stem cuttings. Perennial sunflowers to not grow true from seed, and some of the hybrids do not even produce seeds. On occasion, they may develop powdery mildew. If so, thin them out to improve air circulation or move to a different spot with better air circulation.

Varieties of interest:
Helianthus x multiflorus: Probably one of the more popular varieties. A cross between the annual sunflower and a thin-leaved perennial variety called H. decapetalus. Look for 'Loddon Gold' with lots of double, bright yellow blooms. Grows to be about 6-feet-tall.

Additional varieties:
'Capenoch Star': single, light-yellow blooms and only gets to be about 4-feet-tall.
'Willowleaf Sunflower' (H. salicifolius): Great foliage, similar to that of cosmos. Single, bright-yellow blooms in mid-fall. Height: 7-10 feet.
'Soleil d'Or': Yellow pompom-like blooms throughout the summer. Height: 4-5 feet.
'Low Down': Profuse bloomer. Dwarf. Height: 12 inches.

References:

Hodgson, Larry. Perennials for Every Purpose. Emmaus, PA: Rodale Organic Living Books, 2003.

Rogers, Marilyn, ed. Beautiful Perennials. Des Moines, IA: Meredith Books, 2006.