Grown mainly for their fragrant summer flowers, which are individually tiny but borne in striking clusters 34 in. across. Attract both butterflies and hummingbirds. Although most often treated as annuals, they can be grown as short-lived perennials in the Tropical South. Plants can be massed in flower beds; they also look great in window boxes and planters. Provide well-drained soil.
H. amplexicaule 'Azure Skies'. Perennial in MS, LS, CS, TS; USDA 7-11. Selection of a South American species. Grows 1 ft. tall, spreading up to 1 ft. across. Narrow, deep green, crinkly leaves make a nice backdrop for the lavender blooms. Very heat and drought tolerant.
H. arborescens. COMMON HELIOTROPE. This old-fashioned favorite from Peru is prized for its showy, vanilla-scented flowers. Plants grow 1112 ft. tall and wide. Dark green leaves have an overall purplish cast; they are 13 in. long, crinkled, and hairy, with sunken veins. Recommended selections include white 'Alba', deep purple 'Black Beauty', and deep violet-blue 'Marine', with blossom clusters up to 10 in. across. The Regal Hybrids sport rose and lavender flowers on the same plant. Hybrid 'Simply Scentsational' grows 2 ft. tall and 1 ft. tall; its softly fragrant, pale lavender blooms have white centers and golden yellow throats.
In Southern gardens, common heliotrope grows best with morning sun and afternoon shade. Pinch young plants to encourage bushy growth. If growing as a perennial, prune back hard in early spring. Be sure to keep watered during dry spells.