Popular as outdoor bedding plants, heliotropes (Heliotropium arborescens) can also be grown indoors as houseplants—adding a splash of color and pleasant aroma to your living space. In recent years, as the plant gained popularity for outdoor gardeners, breeders have introduced new varieties with different colored flowers, but the purple heliotrope remains the standard.
Unfortunately, all parts of the heliotrope plant are considered toxic to animals. Despite their intoxicating smell, heliotropes are not particularly palatable plants, which keeps most pets and animals away from them. Regardless, you should ensure that this houseplant is kept out of reach of any curious four-legged family members.
|Botanical Name||Heliotropium arborescens|
|Common Name||Heliotrope, garden heliotrope, cherry pie heliotrope, common heliotrope|
|Plant Type||Perennial, shrub|
|Mature Size||1-2 ft tall, 1 ft wide (indoors); 1-3 ft tall, 1-2 ft wide (outdoors)|
|Soil Type||Moist but well-drained|
|Soil pH||Neutral, alkaline|
|Bloom Time||Summer, fall|
|Flower Color||Purple, white|
|Hardiness Zones||9a, 9b, 10a, 10b, 11a, 11b|
|Native Area||South America|
|Toxicity||Toxic to pets|
While they are typically grown outdoors in garden beds and planters, heliotropes can also be grown indoors as houseplants with the proper care. Besides providing the correct growing conditions, it is important to ensure that you plant your heliotrope in a potting container with drainage holes. Since heliotropes enjoy consistently moist soil, proper drainage is important in ensuring that the soil does not become waterlogged and the roots don’t rot.
Heliotropes are full sun plants that require several hours of direct sunlight in order to bloom. This can be tricky to achieve indoors, unless the plant is situated in a west-facing window or provided with a grow light.
A loamy, well-draining potting soil is best for growing heliotrope indoors. Most standard houseplant soil mixes will work well, or you can create your own loamy mix by combining one part peat moss or coco coir, one part perlite, and one part potting soil.
Keep the soil evenly moist but not soaking, and don’t let the soil dry out. Cut back on watering slightly during the winter once the plant has stopped blooming.
Temperature and Humidity
Heliotropes enjoy warm, dry conditions which makes them well-suited to indoor growing. They don’t enjoy overly hot or humid weather, and they are very sensitive to cold temperatures. They can grow outdoors year-round in USDA zones 9 to 11.
These flowering plants are heavy feeders and will require regular fertilization throughout the active growing period. Fertilizers that are high in phosphorus are best for encouraging blooming, otherwise, balanced fertilizers are also appropriate. Avoid nitrogen-rich fertilizers which will encourage foliage growth and inhibit flowering. Fertilize your plant every 2 to 3 weeks during the spring and summer.
Types of Heliotrope
There are lots of different varieties of common heliotrope to choose from, but the most common flowering cultivators include:
- Heliotropium arborescens ‘Princess Marina’
- Heliotropium arborescens ‘Mary Fox’
- Heliotropium arborescens ‘Florence Nightingale’
- Heliotropium arborescens ‘White Lady’
- Heliotropium arborescens ‘White Queen’
Pruning is an important part of caring for heliotrope, even indoors. Regular pruning and deadheading will encourage consistent blooming throughout the growing season as well as a fuller growth habit.
Heliotropes can be propagated by stem cuttings in soil anytime during the active growing season (spring and summer). In fact, starting cuttings from an established outdoor plant may be the easiest way to start growing this flowering shrub indoors. To propagate heliotrope by cuttings, follow these steps:
- Take 4 to 5 inch stem cuttings from an established plant, being sure to cut just below a leaf on the stem. You should also take cuttings from stems that are still green and fleshy—avoiding woody stems.
- Remove the leaves from the bottom half of the cutting and dip the end in rooting hormone.
- Place the cutting(s) in a pot of pre-moistened soil and put the pot in a location that receives bright, indirect light.
- Keep the cuttings evenly moist, and avoid exposing them to direct sunlight.
- After a few weeks the cuttings should begin to root, at which point you can start slowly introducing the cuttings to more direct sunlight.
How to Grow Heliotrope From Seed
In addition to propagation, heliotropes can also be grown from seed. When grown as a houseplant, you can technically start the seeds at any point during the year, but traditionally seeds are started 10-12 weeks before the last frost. A seed warming mat is required for successfully starting heliotrope seeds as they should be kept at a temperature between 70-75 degrees Fahrenheit (12-24 degrees Celsius). Keep the soil consistently moist, and the seeds should germinate within 28-42 days.
Heliotropes are not particularly pest or disease-prone, especially when grown indoors; however, you should keep an eye out for a few common houseplant pests. Aphids, mealybugs, spider mites, fungus gnats, and whiteflies can all spread from other houseplants and become a problem for your heliotrope. Treat infected plants with insecticidal soap or neem oil until the infestation resolves.
How to Get Heliotrope to Bloom
It can be more difficult to get heliotropes to bloom indoors since they usually receive less sunlight, which is an important requirement for healthy, consistent blooms. To encourage prolific blooming, ensure that your heliotrope has a bright, sunny location indoors; fertilize regularly during the spring and summer, and keep the soil consistently moist. If you are still struggling to get your heliotrope to bloom indoors, you may consider moving it outdoors for the warmer spring and summer months and overwintering it indoors as a houseplant.
Common Problems With Heliotrope
Heliotropes are generally low-maintenance and problem-free, however they can experience more issues when grown indoors as a result of improper light or watering. Keep an eye out for the following problems.
If your heliotrope is dropping leaves, this is an indication that it is not receiving enough moisture, and your watering schedule needs to be improved. Ensure that you are keeping the soil evenly moist and not allowing it to dry out.
Heliotropes not blooming indoors usually means that they don’t have enough sunlight, or don’t have enough water. Ensure that you are also using a fertilizer that is high in phosphorus, which will encourage blooming.
Are heliotropes toxic to pets?
Yes, according to the ASPCA, all parts of the heliotrope plant are toxic to animals if ingested.
How big do heliotropes get indoors?
This compact shrub usually tops out at about 1-2 feet tall when grown indoors, but you can control this with regular pruning and shaping if you wish.
How often should you repot a heliotrope plant?
Heliotropes have a moderate growth rate and should only need to be repotted every 1-2 years depending on the size of your initial pot and your growing conditions.