I bought this thing on a whim at the wildflower center sale last fall. Hibiscus grandifloris is not properly native to Central Texas; it's a disappearing element of American coastal lagoons and persists mostly in the Carolinas. This one put out its first flower this morning, and wow! Spectacular.
The lower leaves turn yellow if watered from Austin tap, so I've been hoarding rainwater and dehumidifier condensate for it, and adding acidifying soil amendements, and that seems to keep it happy.
by Texas_Naturalist