I purchased a verbena bonariensis at the local flea market. I had admired this plant in photos, but never dreamed I would find one for sale at a flea market!
I have delighted in its blooms. But I'm not the only one! The butterflies have been going crazy over this plant's tiny little blooms, too.
Verbena bonariensis grows to about 4 ft tall, on tall, thin sticks, is a perennial in zones 7 through 10, and is supposed to reseed like crazy. (In some areas, it may become invasive.) It doesn't add much visual weight to the garden, but it's perfect for adding in between or behind plantings. Full sun, drought tolerant. (Perfect for my hot, dry, Texas garden!)
If you want to grow verbena bonariensis, try finding it at your local flea market. Or, for a more reliable source, you could try growing it from seeds. Then stand back and wait for the butterflies!