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Missouri Environment & Garden



AUTHOR

David Trinklein
University of Missouri
Division of Plant Sciences
(573) 882-9631
trinkleind@missouri.edu

African Violet: Nature’s Cure for Winter Blahs

David Trinklein
University of Missouri
(573) 882-9631
trinkleind@missouri.edu

Published: January 1, 2010

The dull, dark days of January are enough to dampen the spirits of even the most optimistic amongst us. The holidays are over and spring is not even close, leaving many avid gardeners with an active case of “cabin fever”. Working with plants has been proven to be highly therapeutic and few house plants give more while asking for less than does the African violet. They thrive in most interior settings, provide nearly continuous color and are inexpensive to purchase. As we await the upcoming growing season, winter is an ideal time of the year to start (or add to) an African violet collection.

African violet is native to Africa, as its name implies. It was discovered in 1892 by Baron Walter von Saint Paul, German governor to the African province now known as Tanzania. He found the plant growing in shady areas of the Usambara Mountains and referred to it as his “Usambara violet”. Later it was given the scientific name of Saintpaulia ionantha to honor the gentleman who discovered it. There are more than twenty species in the genus Saintpaulia most of which are similar to S. ionantha in appearance. All are members of the Gesneriaceae family which includes other common flowering house plants such as those in the Achimenes, Gloxinia, Sinningia and Streptocarpus genera.

Von Saint Paul sent seeds of his discovery to his native Germany where it enjoyed some success as a houseplant. It slowly spread to other European countries as a houseplant and was brought to the United States in 1926 when a California firm imported its seeds from German and British greenhouses specializing in the plant. Since that time it has been developed into more cutivars than any other flowering houseplant. The African Violet Society of America’s “Master List of Species and Cultivars” contains the names and descriptions of nearly 10,000 registered cultivars.

Early hybridization of this plant involved the crossing of similar Saintpaulia species in the quest to obtain more robust plants. The result was violets with improved horticultural attributes but only with blue flowers. The reds (wines), whites and pinks that we enjoy today are the result of American hybridizers working in the 1930’s and 1940’s. The harder to achieve coral pink and coral red were added later. Yellow is the latest flower color to be developed.

In addition to breeding for different flower colors, hybridizers also have developed multi-colored blossoms, with petals that are striped, spotted or having edges of contrasting color (picotee appearance). Other characteristics improved include petal count, blossom count, and blossom shape.

Hybridizers also have developed variation in leaf shapes and coloration. Perhaps the biggest achievement in this area was the development of African violets with variegated leaves. Leaves with markings of white, pink or some other contrasting color are now readily available and add to the novelty of this popular plant. There are few other plants that will flower as well in low light conditions as African violet. They require at least 600 but no more than 1500 foot candles. This usually can be provided by placing the plants in windows with bright light but no direct sunlight. Some midwinter sunlight is not harmful, but avoid it at other times of the year. Bright north or east windows are usually satisfactory. If no suitable window space is available, plants grow very well under fluorescent light. Place cool white fluorescent tubes about 10 to 14 inches above the plants and illuminate 14-16 hours daily.

Since the African violet is native to warm areas their location in the home must be kept warm. Maintain night temperatures between 65 and 70 degrees Fahrenheit; day temperatures should be 10 degrees warmer. Do not expose plants to temperatures below 60 or above 80 degrees Fahrenheit.

Soilless growing media produce plants with good growth and flowering although some violet fanciers prefer using soil rich in humus. If soil is used it should be sterilized to reduce the risk of disease infestation. Soilless mixes are considered to be biologically inert and do not need to be sterilized.

Keep plants uniformly moist but not wet since they are easily killed by excess moisture. Wick watering using a candle wick or nylon twine extending from the growing medium via a hole in the bottom of the pot to a water/nutrient reservoir elow the pot works well. Plastic tubs used to hold margarine can be used for the latter. Leaf spotting can be a problem when water 10 degrees above or below the leaf temperature contacts the leaves. Therefore, if overhead watering is practiced, use water that is room temperature and try to keep it off the leaves.

Also, relative humidity is important and most homes have low humidity, especially during winter months. To increase the relative humidity around plants, place them on shallow trays of gravel containing water. Home humidifiers also work well.

If located properly and watered regularly, African violets need little other care besides occasional fertilization. Use either special African violet fertilizers or a houseplant fertilizer high in phosphorus. A very dilute fertilizer solution at each watering keeps growth constant and eliminates any chances of over fertilization. Pale green leaf color may indicate too much sunlight or low fertility. Do not use water softened by a system using salt in the process.

Mealybug is the most troublesome pest of African violets. New plants should be quarantined several weeks before introducing them to your collection. If mealybugs appear, swabbing them with isopropyl (rubbing) alcohol using a cotton swab can be an effective means of control unless populations are excessive.

African violets seldom need pots larger than 4 inches in diameter. The danger of overwatering and development of root and crown rots increases if pots are too big. Old plants sometimes develop long woody stems. The tips of these plants may be cut off and rooted to form new, more compact plants. However, plants developed from leaf cuttings are generally more vigorous and bloom more abundantly.

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REVISED: October 23, 2012