The endearing African violet

They’re small, they’re cute and they’re easy.. — Avital Pinnock/Creative Commons

African violets may be the world's most popular houseplants. Their ease of culture and year-round blooming habit recommend them, while their wide variety of flower color and shape endear them to collectors.

African “violets” aren’t true violets at all, but members of a large family of tropical plants called Gesneriads (jez-NAIR-i-eds). They hail from Africa and are natives of the Usambaras, ancient cloud forest mountains of northern Tanzania.

You can buy African violets cheaply at mass market retailers or you can seek out the latest hybrids through specialty suppliers. Once you get your new plant home, you'll want to refer to growing tips from the experts. Here are some points to keep in mind:

Potting up - These plants like a light, quick-draining mix that won't pack down or lose its porosity. Most experts recommend a mix of 1/3 peat, 1/3 vermiculite and 1/3 perlite.

Suppliers and many garden centers often sell bags of pre-mixed potting medium formulated especially for African violets. Bear in mind that these plants usually bloom most freely when they are slightly pot bound. Don't choose a pot much larger than the root mass, and when repotting move up only to the next size container.

Plants will exhaust the medium in a matter of months. Mini and semi-mini violets need repotting every three to four months and standards require repotting every six months or so. Whether relocating a new plant to a favorite pot or repotting to keep growth vigorous, don't press the growing mix around roots; instead, just tap the pot on a hard surface to settle the soil without compacting it.

Lighting - African violets are light-hungry plants, craving 10 to 14 solid hours of bright, but filtered, light. Many find success growing plants on windowsills - generally, an eastern exposure works best - but winter's short days almost guarantee that you'll need to supplement natural light with artificial. These plants don't want direct sun, which can bleach their leaves.

Nearly all experienced growers with large numbers of plants array them on multi-shelved stands outfitting with fluorescent fixtures. You can buy such stands ready-made for $300 or so, or assemble one yourself from plastic plumbing pipe for under $100. A failure to bloom is most often caused by inadequate light and the failure to feed regularly.

Temperature and air circulation - The African violet is happy where you are, enjoying daytime temperatures of 72 to 75 degrees and nighttime temperatures a few degrees cooler. Protect them from drafts or situations where temperatures fall below 55 degrees and they'll be happy. An aversion to chill also applies to the African violet's roots. Don't give yours the shivers by dousing with ice-cold tap or well water. Instead, bring water to room temperature before quenching your plants' thirst.

African violets enjoy good ventilation, and may contract powdery mildew, a disfiguring white coating affecting leaves, in stuffy rooms with little air flow. Some growers keep fans going to stir up the air.

African violets bloom year round. — MJI Photos/Creative Commons

Watering and humidity - Correct watering might be the critical skill in raising African violets. Certainly, the easier way to kill your little plant is by over-watering. Since getting water in the crown or on the leaves can lead to rot, many growers adopt a system of bottom watering.

This can be accomplished either by setting pots on a moist capillary mat or outfitting pots with wicks, which will allow roots to draw up moisture as needed. Wicks can be fashioned from any synthetic material - ordinary acrylic knitting yarn is a favorite.

African violets also enjoy a higher humidity than often is found in heated homes during the winter. Running a humidifier or setting plants on trays of wet pebbles will help; growing numbers of plants together also boosts humidity immediately around the pots. Because of the susceptibility of leaves to water damage and rot, misting is not recommended.

Fertilizing - Since African violets have no dormant period and can bloom almost continuously, they need to be fed regularly to maintain peak vigor. A gradual loss of leaf color or a refusal to bloom often are signs that fertilization is needed.

Some growers dose with a balanced water soluble fertilizer like a 20-20-20 formula every four to six weeks. Others get good results by using a solution at 1/4 strength, i.e., 1/4 teaspoon to 1 gallon of water, every time they water.

Propagation - Few plants are easier to propagate than African violets, which can produce dozens of new seedlings from a single leaf of the parent plant. This characteristic makes it easy to duplicate plants to share with friends or offer for sale.

Plants also produce viable seed, but this is generally only used by hybridizers who have plenty of room in climate-controlled greenhouses to grow plants on to blooming size - generally in four to six years.

To propagate from a leaf, choose a healthy leaf near the base of the plant. Cut it off, leaving about 1/2 inch of stem attached to the leaf. Set the stem in a small pot filled with equal parts of vermiculite and perlite and keep moist. Many growers pop the entire pot into a small sealed plastic bag to maintain humidity.

In 4 to 8 weeks, new plants should develop. When large enough to handle, each may be potted up individually.

Pests and diseases - The only serious pests commonly found on African violets are mealy bugs or thrips, both sucking insects that undermine the health of the plant and can damage or deform blossoms. Pyrethrum-based pesticides can deal death to these interlopers.

An ounce of prevention is worth a pound of cure. Since pests often hitchhike in on new plants, isolate your purchases for several weeks before admitting them to the company of resident African violets. This will give you an opportunity to spot any problems before they launch an epidemic.