Heliotropes

Heliotropes is the common name for flowering plants in the genus Heliotropium, in the borage family Boraginaceae, and for the ornamental species Heliotropium arborescens. These plants are grown for their showy clusters of fragrant flowers and, in some species, for their foliage.

Most heliotropes are herbaceous perennials or shrubs with simple, alternate leaves that are often rough or hairy. The flowers are small and typically arranged in dense terminal cymes or panicles. Colors range from blue and purple to white or pink. A distinctive feature of cultivated heliotropes is their sweet, vanilla-like scent, especially noticeable in the evening.

The term heliotrope reflects the plants’ historical association with sun-tracking movement. Some heliotrope species exhibit heliotropism, meaning leaves or inflorescences orient toward the sun during the day. Many also show nyctinasty, with rhythmic movements tied to the daily light cycle. The movements are driven by specialized structures at stem joints and are most pronounced in buds or young growth.

Cultivation and use: heliotropes are popular ornamentals in warm temperate to tropical climates and are often grown as annuals in cooler regions. They prefer full sun, well-drained soil, and regular moisture. They are used in borders, containers, and cut flower arrangements. Caution is advised because many Heliotropium species contain pyrrolizidine alkaloids and can be toxic if ingested by humans or animals.

Other notes: the name heliotrope is also linked to the fragrant compound heliotropin (piperonal), historically associated with the flower’s scent and used in perfumery.