Christie, I just planted Helianthus maximiliani this year and I had Black Swallowtails on it this week. It can be invasive, but I am growing it in a location where I think I can control it (famous last words). I didn't grow it from seed, but ordered it from dogwooderitternet on Ebay. He carries lots of butterfly hosts and nectar plants. From a small 3" tall plant, it has grown to about 8' tall this summer, and there are flowers from low stems to high stems, so it's very attractive. It is supposed to be a host for Silvery and Gorgone Checkerspots, and a nectar source for migrating Monarchs. We will see. It has very attract foliage, kinda grey-green.

Susan

I have tithonia diversifolia (sunflower tree) it grows to about 15 feet tall and about 8 feet wide, but can be pruned to maintain a smaller size. Butterflies love it especially gulf fritilary and julia butterflies.
Siam.

Wish I knew the name for them, but the best-growing sunflowers for me are the ones that sprouted under the bird feeder. I (and the butterflies) love mexican sunflowers but they never do very well for me. Sunflower tree (mentioned above) seems to be popular with the butterflies too around here. (Assuming the sunflowers I am thinking of are sunflower tree - certainly tall enough!)

Tithonia diversifolia wouldn't make it through the winter where I am. I grow tithonia rotundifolia as an annual and love it. I wonder if t. diversifolia would flower well if it was grown as an annual.
Susan - I've been seeing checkerspots but haven't figured out which kinds I have. They like my a. tuberosa. I didn't know they use helianthus for a host plant. Thank you.

Summer Sun is supposed to have a long bloom time so I'm hoping someone has noticed whether the butterflies like that one.

I don't know how well the butterflies like them, but Downy Sunflower is very easy to grow from seed and I get volunteers every spring. Each patch also spreads in a controlled manner from year to year. My only complaint is that the stalks fall over so it gets a bit messy and crowds the plants around it. The birds love the seeds in later fall.

Martha

Thank you Martha - I'm not familiar with Downy Sunflower and will look up some more information on it. There are more native sunflowers than I realized. Thanks

Pretty much most plants in the genus Helianthus are perennial sunflowers (with the exception of the species "annus" which is the annual). I've attached info on a few of them. Some of them can be invasive. There's quite a few to choose from, and you can check native plant vendors sites for seeds and/or plants as well for info. I'm enjoying Maximilian Sunflower because it blooms ALL the time, and the bees and butterflies love it.

Susan

Here is a link that might be useful: Perennial Sunflowers

Perennial Helianthus species are easy to start from seed. I've grown H. maximiliani & H. divaricatus from seed and Helianthus 'Lemon Queen' which is a hybrid makes a few seedlings in a fairly dry garden. These are all aggressive growers and spread impressively via rhizomes, so I grow them in a more naturalized setting. I also have Heliopsis 'Summer sun' and started the species from seed (another easy germinator).

The perennial sunflowers are wonderful because bees love them, and the Goldfinches love the seeds. But they are not a big butterfly attractor in my gardens and only occasionally see a butterfly on them. Neither is the Heliopsis thus far (the seedlings haven't bloomed yet).

Another tall, yellow bloomer I'm growing that DOES attract more butterflies is Cup plant - Silphium perfoliatum. It is a coarse plant but has interesting leaves and makes pretty clusters of yellow flower which the bees, Eastern tiger Swallowtails, and even the hummers nectar off regularly. The Goldfinches and other little birds LOVE the seeds on these.

H. angustifolius/swamp sunflower is a perennial that's frequently visited by butterflies - it doesn't grow in swamps, so I don't know why they call it that.
Sherry