Heliotrope is best known for its cherry-pie fragrance, which is why its common name is the Cherry Pie Plant. Heliotrope has clusters of flowers on each stem that bloom from summer until early fall. Plan to plant heliotrope seeds indoors about 10 to 12 weeks before the anticipated last frost. Heliotrope is typically an annual plant, however in USDA hardiness zones 9 to 11, they can be grown as a perennial.
Fill a container with soil 1 to 2 inches from the top rim. Use all-purpose potting soil, mixed with 25 percent sand. For a container, use a planting tray, especially if they are to be transplanted outdoors.
Scatter the seeds and cover them with an additional ¼-inch of soil. Water the seeds so that the soil is only slightly moist. Place a tray in a warm location between 60 and 65 degrees F, if possible, and keep the soil slightly moist. The seeds will germinate in about two weeks. Keep only the strongest seedlings and pinch them back as they grow to ensure that the heliotropes grow to be thick and bushy.
Move the container to its final location in about 10 to 12 weeks and only outdoors if the last frost has passed. Generally, a couple of plants can remain in one container. Alternatively, transplant the plants outdoors in a sunny or partial shady location. Space multiple outdoor plants about 1 to 2 feet apart and cover the planting site with 2 to 3 inches of mulch, such as pine needles or bark mulch, to help heliotropes retain water and maintain even soil temperatures.
Feed the new plants every two weeks indoors or every 4 to 6 days outdoors with a slow-release, 10-10-10 fertilizer and follow dosing instructions on the label.