Heliotropium, also commonly referred to as ‘heliotrope’, is a genus of flowering plants in the Boraginaceae family containing around 325 species. They are popular flowering perennials thanks to their stunning flowers and pleasant aroma and are synonymous with the ‘old cottage’ garden style. Heliotrope flowers grow in one-sided clusters that follow the sun, which led to their name which is directly derived from the Greek words helios (meaning ‘sun) and tropos (meaning ‘to turn’). Some gardeners describe the scent of the flowers as vanilla, while others insist they smell like cherry pie! Learn how to grow these attractive perennials in your garden.
Heliotropes are highly toxic to cats, dogs, and livestock and can lead to death if ingested. If consumed in large quantities, it can also be toxic to humans. Plant with caution.
|Common Name||Heliotrope, cherry pie plant|
|Mature Size||1-4' tall|
|Sun Exposure||Full sun|
|Soil Type||Rich, well-draining|
|Bloom Time||Summer, fall|
|Flower Color||White, lavender, purple|
How to Grow Heliotropes
Heliotropes are temperate perennials that are native to the subtropical regions of Peru. When grown outside of their native range, heliotropes are usually grown as annuals as they are highly frost-tender. They are considered low- to medium-maintenance plants that benefit from some regular pruning and care. Regular pinching and deadheading will encourage more veracious blooms and a bushier, denser growth habit. Heliotropes are not susceptible to any serious pests or diseases.
Heliotropes are full sun plants that require at least six hours a day of direct sunlight. However, they prefer morning sun and in hot climates, intense afternoon rays may burn the delicate flowers. A location that receives bright morning sunlight and light shade in the afternoon is ideal.
Heliotropes require lots of water in order to thrive. Keep the soil evenly moist, but not waterlogged, and don’t allow the plants to dry out. When grown in containers, heliotropes will need to be watered significantly more often as the plant will absorb the water more quickly.
Plant heliotropes in rich, loamy soil that is well-draining but retains some water. They prefer soil that is rich in organic matter, with a pH between 6.6 and 7.3. Heliotropes do not do well in heavy clay soils as they cannot tolerate ‘wet feet.’
Temperature and Humidity
Heliotropes grow best in dry climates with warm days and cool nights. They do not do well in overly hot or humid weather and they are highly frost-tender. They grow well in USDA zones 9 through 11.
Heliotropes are notoriously heavy feeders that need to be fertilized regularly throughout their growing season. When grown in the garden, heliotropes should be fertilized at least once a month. When grown in containers, they should be fertilized as often as every two weeks. Use a fertilizer high in phosphorus that is meant for flowering plants.
Are Heliotropes Toxic?
All parts of heliotrope plants are highly toxic to dogs, cats, and livestock when ingested, leading to liver failure and even death. If consumed in large quantities, they can also be toxic to humans. If you are worried about curious pets or children getting into these plants, planting them in hanging baskets or containers that are out of reach is recommended.
There are many different varieties of heliotropes, but the most popular heliotrope varieties are as follows:
- Heliotropium arborescens
- Heliotropium amplexicaule
- Heliotropium anomalum
- Heliotropium curassavicum
- Heliotropium indicum
Growing Heliotropes in Containers
Heliotropes make great container plants as they are small plants, that are not invasive (i.e. they won’t take over your container garden!) and they are not prone to any serious pests or diseases. Growing heliotropes in containers also means that they can be easily overwintered indoors if desired. Keep in mind that heliotrope plants grown in containers will require significantly more water than plants grown in the garden.
Regularly pruning your heliotrope plant will encourage consistent blooms and a fuller growth habit. You can begin pinching back the stems and flowers in the early spring to encourage more lateral growth. This may delay the initial bloom but you will be rewarded with larger and more prolific blooms throughout the rest of the season.
How to Grow Heliotropes From Seed
Growing heliotropes from seed is the easiest and most popular way to grow these flowering perennials. Seeds should be started indoors 10-12 weeks before the last frost to ensure that the plants have time to bloom before the first frost hits in the fall. Heliotrope seeds should be kept at a temperature between 70-75 degrees Fahrenheit (12-24 degrees Celsius) and should germinate within 28-42 days. Once the last frost has passed, the heliotrope seedlings can be transplanted into the garden or a container outdoors.