(firecracker plant) (Cuphea sp.). Gardeners who have very hot summers have come to appreciate many of the options among cupheas. Heat tolerance is very high for most. Tubular red flowers attract hummingbirds. Size and habit vary according to species. The cigar plant (C. ignea) has dark green pointed leaves and a tightly branched habit to 12 inches tall. USDA Zones 10 to 12. Very frost sensitive; dies to the ground in Zones 8 and 9 but usually grows back quickly in spring. Other cupheas that are great for heat: Mexican heather (C. hyssopifolia), batface cuphea (Cuphea llavea), candy corn (C. micropetala) and giant candy corn (C. melvillea).