Verbena bonariensis. Georgeous lilac clusters atop long airy stems that reach 1 metre or more. V. bonariensis is heat and drought tolerant and blooms from July until frost. If there is a bee in the vicinity, it will be on this flower! It is the perfect plant for splashes of mid-border colour. This tender perennial is supposed to be hardy in zones 7 through 10 but we find that it overwinters in our zone 5 garden as long as there is snow cover. Even if your plants succumb, they will deposit t..