Hollyhocks
(Alcea rosea)
Pink, purple, peach, red, white, yellow or near-black flowers completely cover 8-foot stalks from top to bottom. The large-leaved plants are biennial, which means they live for two years and bloom only in their second year, but they do self-seed, so there will always be more on deck. Plant them in full sun in the North and part shade in hot climates, and provide a fence, trellis or stake for support.