I ordered from SRG about 5 times, Love that cheap shipping! My absolutely biggest Echinacea came from Plants Delight, I got a shrub and a small tree from, Lazy S's and I got 3 winter Berries from Bluestone. Be sure to re-pot them because the coco pots do not biodegrade as quickly as they should and the roots will be trapped in there. Also they dry out real fast if you leave them out, I had a Hosta that dried out and blew away before I even realized anything was wrong.
They do have a good selection of butterfly and hummer plants by category. I've heard good things about Romence Gardens.
