Perennial sunflowers adored by birds and butterflies

I sat down to write about what I thought was a narrowed-down topic on keystone species: native perennial sunflowers. As a group, these are excellent, late-blooming, carefree bursts of yellow that are vitally important keystone species for most of North America. From a wildlife perspective, they are tremendous host plants (supporting 75 species of caterpillars!), they provide excellent late-season nectar, and the seeds are a beloved food for finches and migrating birds. No wonder they get top-of-the-list rating for biodiversity value.

But there are so many of them available in the trade, that I quickly ended up with a spreadsheet to keep track of them all. And when I think about the kinds of situations most people have in their landscapes, I feel that most of these Helianthus would be difficult to use with long-term success. (But wait--scroll down for the easier ones to use.)

The primary reason: most of them are  beautiful but rambunctious, rambling, gangly giants! Perfect for only a few, choice situations— along a tall, sunny fence, or in a swale, for example, where I might choose Helianthus angustifolius, Swamp sunflower. (Thank you to Erica Weick for the photo, left, of Swamp sunflower).

Or to fill a large, damp, shaded area, where you could try Helianthus divaricatus, Woodland sunflower). This aptly named sunflower prefers part sun or lightly shaded areas, and can really thrive at the edges of a woodland.

And of course at the extreme far end of the aggressiveness continuum there is the notorious Helianthus tuberosus, Jerusalem artochoke. It is grown as a food crop, but recommended only in areas well-isolated from any gardens per se, since in addition to being a rapid colonizer, its much deeper root system makes it super difficult to eradicate once established.

That's only a few of them! But instead of cataloguing all those giants, in this article I'm going to focus in on one, smaller group of SHORTER, super-useful cultivars of Helianthus salicifolius/Willow-leaf sunflower.

If you have the space, by all means welcome this one as a straight species! But know the plant's level of exuberance: Helianthus salicifolius, straight species, will get 6-9' tall! Each 3' wide plant will spread by rhizomes to form a colony in a pretty short period of time. If you have the space, the late-season show is spectacular and the birds will be deliriously happy with the seeds afterward! It is always best to use the straight species if you can.

If, however, like me, you have a normal suburban yard and not so many acres to work with, you can still have a version of this powerhouse plant for your landscape. Lucky for us, willow-leaf sunflower has been a cooperative plant, providing several excellent, shorter cultivars. Here are three below that are often available where native plants are sold.

3 SHORT, PERENNIAL SUNFLOWERS THAT SPREAD MORE MANAGEABLY:

Helianthus salicifolius 'Low down'. At barely a foot high, this is the reigning Champion Shortest Cultivar for this species. Blooms September-October, a dense cluster of deep yellow bloom atop a mound of slivery-thin green leaves. Tolerates deer and clay soil, and moderately drought tolerant once established. Spreads 18" wide, and prefers full sun, but will adapt to part sun with fewer flowers and a bit of floppiness.

Helianthus salicifolius 'First Light' is 3-4' tall and flowers are more of a lemony color. Otherwise it is very similar to 'Low down' in preferences and bloom time. All of these cultivars will spread slowly over time by rhizomes, but their seed is reported to be sterile. Because of the spreading by rhizomes, clumps can be divided every 3-4 years in spring or fall.

Helianthus salicifolius 'Autumn Gold' is in the middle, at roughly 2' tall. Like the others, it also blooms from September til hard frost in October. Its narrow leaves are dark green, and except for the height, it is very similar to the other two.

I'll be experimenting with 'Autumn Gold' in part sun and very sandy soil this year. Do you have any of these in your landscape? I'd love to hear what the conditions where, and how they have done.

On another topic, I am offering design consulting by video call this year, and it's a been a lot of fun! Nurseries are selling more plants than ever this year because many of us find ourselves with the luxury of time at home to work in the gardens! Hooray!

Enjoy and stay safe!
Chris