Also called cherry pie plants for their inviting fragrance, this old-fashioned summer favorite fairly glows with dark purple blooms. Attractive to hummingbirds, butterflies, and other insect pollinators, heliotropes are excellent container plants and are reliable bedding plants, too. Learn how to plant, grow, and care for heliotropes.
About Heliotropes
The heliotropes we grow in our gardens are most often Heliotropium arborescens or hybrids thereof.
Though considered a tender perennial shrub in their native South America, heliotropes are usually treated as an annual in zones 1 to 8. Otherwise, they can get a bit stringy or loose-formed when grown for several years.
As annuals, they grow about one to two feet tall and wide and are mildly shrubby plants with colorful clusters of fragrant star-shaped flowers. They are heat lovers and will continue to flourish in hot summers.
What Color Are Heliotropes?
Traditional heliotropes usually have towering, deeply purple blossoms with dark green, deeply veined, and textured foliage.
Newer varieties may have lavender or white blooms and become bushy plants covered in tiny cherry or vanilla-scented flower clusters. Although not native, the clusters of flowers are a favorite of pollinators.
What Do Heliotropes Smell Like?
They are intoxicating! Many gardeners describe the flowers as having a sweet cherry-like scent (hence, why they’re known as cherry pie plants), while others describe a vanilla grape scent.
How to Garden With Heliotrope Plants
With their spreading nature, heliotropes make great bedding plants. They work well in mixed borders (placed at the front) and are also often used on slopes and hillsides.
Flower companions for heliotrope include black-eyed Susan (Rudbeckia hirta), floss flower (Ageratum), geranium, alyssum, lantana, stock, saliva, and zinnia. You’ll have a garden with pollinators and hummingbirds!
Thanks to their lovely fragrance, heliotrope also works well in containers on the patio or deck, in hanging baskets, and in window boxes.
Heliotropes like fertile, loose, well-draining soil with some organic matter. If planting them directly in the ground, add compost. Use any high-quality potting mix in containers.
Full sun is best, although a bit of afternoon shade is helpful in southern locations. While they will grow in partial sun, their size and bloom power may be limited.
When to Plant Heliotropes
Heliotropes are not tolerant of cold weather. Wait to set out or transplant them until the last of the spring frosts have passed and the weather has warmed a bit.
How to Plant Heliotropes
Most heliotropes are purchased ready for transplanting in spring from garden centers. If your heliotrope was growing inside a greenhouse, ensure you harden it off prior to transplanting. They are as easy to plant as other small annuals. A little slow-release fertilizer tossed in the pot or the soil at planting is usually enough for a season of blooms.
Loosen the soil, remove weeds, and add some compost.
Dig a hole as deep and a little wider than the current rootball.
Trim off any girdling or circling roots. Score the edges of the rootball if the plant is potbound.
Test fit the plant in the hole. Adjust so the plant is at the same soil level as in the pot.
Fill in the hole with the soil you removed and tamp it in with your hands to remove any air pockets.
Water well and apply mulch.
Heliotropes headed for a container garden can be repotted in their new homes with good-quality potting mix. Make sure the drainage holes in the planter are clear, and choose other moisture-loving plants as companions in larger pots.
Heliotropes can also be started from seed, although it can be a little challenging. Seeds are easy to find online. Be patient; heliotrope seeds can take up to a month to germinate.
Begin 10 to 12 weeks before your last frost date.
Sow seeds in seed starting mix, lightly covering with vermiculite or media.
Mist and cover with a humidity dome or plastic wrap to conserve moisture.
Provide supplemental lighting, ten or more hours per day depending on the strength of your lights.
Remove the humidity covering once most seeds have sprouted.
Transplant to individual pots; 3 to 4 inch pots work well once the seedlings have two true leaves.
Growing
Heliotropes like a consistent supply of moisture, whether in a pot or in the ground. When planted in the ground, use mulch to reduce soil drying. Container-planted heliotropes may need frequent watering. Water the soil directly from under the foliage to minimize fungal issues.
Provide weekly water in the absence of rain. Heliotropes in pots will need watering as often as daily.
While deadheading isn’t required, it will improve the appearance of your heliotropes. If they start to get straggly, give them an even haircut (pruning) to encourage more bushy growth. Flowering will resume shortly on the new growth.
Fertilizer container-grown heliotropes with a diluted fertilizer biweekly or monthly when watering. Those grown in the ground might not need extra nutrients if you added compost or slow-release fertilizer when they were planted.
Types
‘Augusta Lavender’ is a hybrid with light lavender blooms which transition to white with golden centers. Its mature size is about two feet tall by 2-3 feet wide and it is more heat-resistant than old varieties.
‘Alba’ is a white-flowering variety that forms a nicely mounded shape about 30” in all directions. It’s one of the most fragrant heliotropes, does very well in containers or in the ground, and exhibits more perennial tendencies than many other varieties.
‘Marine’ is the classic heliotrope look with deep purple clusters of blooms on a modest-sized plant. The vanilla fragrance, textured depth of foliage, and bloom color make this a favorite, and it’s easy to find in garden centers in spring.
Gardening Products
Wit and Wisdom
Follow the sun! This plant’s name comes from the word heliotropic, which means to move with the sun—exactly what the flower heads do. They track the sun across the sky and reset for the morning.
Andy Wilcox is a flower farmer and master gardener with a passion for soil health, small producers, forestry, and horticulture. Read More from Andy Wilcox