Answer: There are a few tender perennial species of ageratum, mostly small shrubby plants, native to South and Central America. They aren't hardy as far north as Virginia, I'm afraid. Some annual species of ageratum self-sow (plants arise from the previous season's seeds). Far North Gardens (16785 Harrison, Livonia, MI 48154; ph# 810/486-4203) carries A. conyzoides, a shrub that grows to about 3' tall and has mauve, blue or white flowers. It's hardy to zone 9. Hope this helps!
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