A highly fragrant, tender perennial, the heliotrope (Heliotropium arborescens) offers large clusters of tiny lavender flowers during the summer and fall. An evergreen, it can attain a height of up to 6 feet when grown in USDA zones 10 to 11. In all other regions the plant is quickly killed by frost and can only be considered an annual.
The heliotrope produces dark-green leaves that measure 3 inches in length and width. The texture of the leaves feels rough to the touch and appears covered in tiny grooves or ridges. When grown in a container the plant rarely attains a height that exceeds 18 inches. To maintain its compact size in both the garden and containers the new growth can be pinched in the spring.
Choose a planting location in full sunlight to partial shade for best flowering. The heliotrope grows best in rich, organic soil that is well draining. For best growth keep the plant moist but not water-logged. It can benefit from a monthly application of general purpose fertilizer such as 10-10-10 or 12-12-12. Water the fertilized area completely when applying.
The flowers of the heliotrope appear non-stop from summer until fall. The flowers are often called "turnsole" because they turn their heads during the day to face the sunlight. During the nightfall the flower heads turn towards the East to await the rising sun, according to the University of Washington.
Often called the "cherry pie" plant, the heliotrope produces sweet, vanilla-scented flowers that remind many gardeners of the sweet aroma of a freshly baked cherry pie. The blossoms can be cut and placed indoors for fragrance-filled bouquets. Remove the spent flower heads of the plant to encourage new flowers to form. The heliotrope flower heads will quickly go to seed once they die. The seeds spread easily in the flower bed.
Pests and Disease
Remarkably disease and pest hardy, the heliotrope suffers from no major problems, according to the Missouri Botanic Gardens. Aphids or spider mites can afflict the plant but are easily washed away using a strong spray of water. Insecticides can also be used for control. Overwintering plants often have whiteflies or mealbugs but both are treated easily with insecticidal sprays.