Browallia Speciosa B. Americana

Fundamental Facts

HARDINESS: Tender
PREFERRED SOIL pH: Neutral to slightly alkaline
PREFERRED SOIL TYPE: Fertile, well-drained
PREFERRED LIGHT: Partial shade
ATTRIBUTES: Blue or white, star-shaped blossoms on compact or cascading plants; for pots, boxes, baskets, beds
SEASONS ON INTEREST: Summer to fall
FAVORITES: Blue-flowered 'Heavenly Bells'; white-flowered 'Silver Bells', drought-tolerant 'Amethyst Bells'
QUIRKS: Needs watering to avoid wilt in hot weather
GOOD NEIGHBORS: Sweet alyssum, bedding geraniums, petunias
WHERE IT GROWS BEST: Partial shade; moist sail
POTENTIAL PROBLEMS: Aphids
CRITTER RESISTANCE: Good
SOURCE: Bedding plants, seeds
DIMENSIONS: 1-2 ft (0.3-0.6 m) tall, 1-1.5 ft (0.3-0.5 m) wide

Browallia in the Landscape

When a plant performs well in a container, it wins general acclaim. But when that plant also bears quantities of purplish blue, 1 in (2.5 cm) wide, star-shaped blossoms, it becomes an instant hero. Browallia are custom made for combining with red-flowered geraniums and white-flowered sweet alyssum for a patriotic display. The browallia palette also includes white-flowered plants, which are welcome to brighten the partly shaded garden niches preferred by this serene summer bloomer.

Although they make good bedding plants, browallias are generally grown in pots. In partial shade, their deep green, 1 in (2.5 cm) long leaves form a tidy mound that spills over the edge of a window box, hanging basket, or whatever container you choose to plant them in. Browallia is a pretty sight even without blossoms, but add the profusion of flowers and you have something truly spectacular.

Selecting the Right Browallia

For prime performance, most browallias grow best in partial shade and with regular watering to prevent wilt. Those conditions please the deep indigo-flowering 'Heavenly Bells' and its white counterpart, 'Silver Bells'. If you occasionally miss a day when watering your containers, or if you have dry growing conditions in your garden, opt for the more drought-tolerant, compact-growing 'Amethyst Bells', which has purple blossoms accented by white centers.

Another browallia has recently stepped into the limelight. B. americana 'Cascade Sky Blue' is an interesting variation that produces quantities of 1 /2 in (1.3 cm) pale violet-blue, star-shaped flowers on plants that form a compact 1-2 ft (0.3-0.6 m) mound. 'Cascade Sky Blue' flowers from early spring until fall and tolerates either sun or shade.

Growing Browallia

The beauty of browallias is that they require so little fuss. But for best results, keep the soil they grow in moderately moist and fertilize regularly. It's easy to see when they are in need: Browallias quickly wilt when thirsty, and the leaves fade to a light green color when they need fertilizer. To keep plants green and in continuous bloom, provide containers with a weekly application of balanced fertilizer, such as a 20-20-20 formulation. Browallias are not prone to insect problems other than occasional bouts of tiny, pear-shaped, sap-sucking aphids, which can be controlled with insecticidal soap.

Increasing the Bounty

You can buy browallias as bedding plants in spring or easily grow them from seed. Sow seeds indoors 10-12 weeks before the last frost. The seeds need light to germinate, so sprinkle them on the surface of a container filled with commercial seed-starting soil moistened lightly with a mister. Set the container on a sunny windowsill or under fluorescent lights, where the soil temperature will stay between 65° and 70° F (18° and 21°C), and keep the soil moist until the seeds sprout. Transplant seedlings into pots when they have two to three sets of mature leaves. Remove growing tips to encourage branching. Growing new plants from stem cuttings is not recommended.