How to Grow Browallia

This long-blooming annual flower brightens up shady spots

Browallia speciosa is a prolific long-time bloomer
Browallia speciosa

Maksym Kapliuk / Getty Images

If you are looking for a low-maintenance annual flower in a shady location and one that blooms prolifically, and for an extended period of time, consider browallia. Botanically, browallia (Browallia speciosa) is a tropical perennial but it’s mostly grown as a warm-weather annual. Boasting bright blue, purple, and white blooms, it's a moderately fast grower with a cushion-like growth habit.

Browallia is especially pretty when cascading down a wall, and its deep green foliage nicely fills a flower bed or rock garden in the summertime. Its flowers attract hummingbirds and it's a popular plant for containers and hanging baskets. If growing from seeds, start them indoors eight to 10 weeks before last frost. Potted plants can be brought indoors for overwintering before the first fall frost.

Botanical Name Browallia speciosa
Common Name Browallia, Amethyst flower, Bush violet, Sapphire flower
Plant Type Perennial grown as annual
Mature Size 1-2 ft. tall, 1-2 ft. wide 
Sun Exposure Full sun to part shade
Soil Type Sandy, clay, loamy
Soil pH Neutral to acidic, acidic, alkaline
Bloom Time Summer to fall
Flower Color Blue, purple, white
Hardiness Zones 10-11 (USDA) 
Native Area South America
Toxicity  Toxic to pets 
Browallia species has masses of star-shaped flowers
Browallia species has masses of star-shaped flowers ShySlug / Getty Images

Browallia Care

Except for pinching back the plants to encourage bushiness, browallia requires little maintenance. Whether you buy browallia seedlings from a nursery or start your own from seeds, make sure that when planting browallia in flower beds or borders, space them at least nine inches apart. Browallia can reseed itself but will only reach the flowering stage in USDA hardiness zone 10 or 11; in all other zones, the growing season is too short.

Light

In hot climates, browallia should be grown in partial or dappled shade. It prefers afternoon shade. In cooler locations, it can also tolerate full sun.

Soil

Browallia needs rich soil high in organic matter with good drainage. Acidic to slightly alkaline soil is best.

Water

Make sure the soil does not dry out and keep it evenly moist but not soggy. Too much water on the other hand will result in mainly foliage and few flowers.

Temperature and Humidity

Browallia is a tropical heat-loving plant. Only plant it outdoors after all danger of frost has passed and temperatures have warmed. Even a very light frost can damage the foliage.

Fertilizer

If you start with good, rich soil, browallia will only need moderate fertilization. Apply a low-nitrogen fertilizer a couple of times during the growing season. As with too much water, excess fertilizer will result in mostly foliage instead of flowers.

Grown in containers however, browallia needs more frequent fertilization, about once a month depending on frequency of watering.


Browallia speciosa in its natural tropical habitat
Ananta Dhungana / Getty Images

Browallia Varieties

Another popular browallia species is Jamaican forget-me-not (Browallia americana). It is often referred to as Amethyst flower or Bush violet—the same common names as Browallia speciosa. It is also grown as an annual that blooms prolifically until the first frost. The difference is that Browallia americana plants have a more shrubby growth habit and might require staking; they also tend to attract butterflies and bees.

Growing in Pots

Browallia is a popular plant for containers and hanging baskets. Keeping in mind that it’s a shade plant, choose a location where the plant is not exposed to direct hot afternoon sun.

Growing From Seeds

Start seeds indoors eight to 10 weeks before the last frost in your area. Because the seeds require light to germinate, just press them lightly into the soil and keep the soil evenly moist and the temperature around 75 degrees Fahrenheit. The seedlings emerge in seven to 21 days.

Before planting them outdoors, the young plants must be hardened off.

Overwintering

It is possible to overwinter your container plants if you have a large, south-facing window. Bring them indoors before nighttime temperatures fall below 40 degrees Fahrenheit, and cut the plants back to a manageable size. Keep the soil consistently moist but not wet.

In hardiness zones 10 and 11, you can also sow browallia in pots in the fall for winter blooming. Start the seeds in small pots and move them to larger containers as they grow.

Common Pests/Diseases

Browallia does not have serious disease issues. They might be visited by soft-bodied insects such as aphids, thrips, spider mites, leafhoppers, and whiteflies. These can be controlled with insecticidal soap but browallia is especially sensitive to chemicals in warm weather, which can lead to leaf damage. Weigh whether it’s a real infestation that needs to be treated, or whether the insects can be removed simply with water from the hose.