African Violets are native to eastern tropical Africa. There is a concentration of species in the Nguru mountains of Tanzania. Several of the species and subspecies of the section are endangered, and many more are threatened, due to their native cloud forest habitats being cleared for agriculture.
African Violets, Saintpaulias are the common name of the section Saintpaulia of the Streptocarpus genus. This section was initially regarded as a separate genus (Saintpaulia). African violets were discovered in 1892 in eastern Africa by Baron Walter von Saint Paul, and these plants was named Saintpaulia in his honor.
IDENTIFY AFRICAN VIOLETS
African Violets are native to eastern tropical Africa. There is a concentration of species in the Nguru mountains of Tanzania. Several of the species and subspecies of the section are endangered, and many more are threatened, due to their native cloud forest habitats being cleared for agriculture.
Saintpaulias are herbaceous perennial flowering plants which grow from 6-15 cm tall, 6-30 cm wide with rounded to oval, 2.5-8.5 cm long with a 2-10 cm petiole, finely hairy, and have a fleshy texture leaves. Plants can be classified as one of several sizes based on its above-ground diameter: Micro (less than 3 inches), Super-mini (3 to 4 inches), Mini (between 4 and 6 inches), Semi-mini (between 6 and 8-10 inches), Standard (between 8-10 to 12-16 inches), Large/Giant (over 12-16 inches).
These plants bloom year round with no specific flowering season, which is probably why they are considered perfect houseplants. The flowers are 2-3 cm in diameter, with a five-lobed velvety corolla, and grow in clusters of 3-10 or more on slender stalks called peduncles. Flower color varies from blue to violet, lavender, pink, red-violet, blue-violet, lavender-pink and white. Flowers may be single, double, semi-double, star-shaped, fringed or ruffled. Some varieties produce flowers with two or more rows of petals on one color with the rest fringed in a different color.
GROWING AFRICAN VIOLETS
Cultural information should only be used as a guide, and should be to be adapted to suit you. Your physical location; where you grow your plants, how much time you have to devote to their care, and many other factors, will need to be taken into account. Only then can you decide on the cultural methods that best suit you and your plants.
Light:
Light intensity is a very important factor in production of quality African Violets. Light recommendations vary by cultivar and season, but a range of 800 to 1200 foot candles is satisfactory. Windows facing north or east provide favorable light conditions and are preferable to those exposed to midday and afternoon sunshine during summer. The sunnier, warmer windows are better in the winter. Cultivars that produce dark green leaves with long petioles may require higher light levels, while varieties with light green foliage may require lower levels.
Plants that receive too much light will be generally stunted, producing brittle leaves, shortened petioles and bleached foliage. Excess light, even for a short duration, can actually burn both flowers and leaves.
Saintpaulias can be easily grown using artificial light. An intensity of approximately 600 foot-candles for 14 to 16 hours per day is recommended. Fluorescent lights are most frequently used and can be arranged in tiers or attached to shelves for a convenient and attractive light source. The tubes should be 12 to 15 inches above the tops of the plants. A shelf containing two or more 20 to 40 watt tubes will grow numerous plants.
Temperature:
An average day temperature of 77°F provides the highest rate of vegetative growth. When the day temperature exceeds 85°F, plant growth and flowering are stunted. Night temperature for Saintpaulia should be warm (68-70°F) for rapid vegetative growth. Plant growth slows at night temperatures of 65°F, and almost stops at or below 60°F. Bench surface heating or under-bench heating pipes are effective for increasing the growth of African violets. Temperature is the main factor used by growers to speed up or slow down flower development.
Humidity:
African Violets grows well at 50% to 70% relative humidity. Low humidity can cause flower petal burn. Where a few plants are concerned, humidity may be increased by setting the pots in watertight metal or plastic trays filled with water and gravel or pebbles. Maintain a shallow level of water in the tray. Do not allow the pots to sit in water; set them on pebbles or on inverted shallow pot saucers.
Substrate and growing media:
African Violets is commonly potted and finished in 4, 4.5 and 5 inch pot sizes. During potting, care should be taken not to plant crowns or tissue-cultured liners too deeply. Their roots are very fine and require a light-weight, well-aerated, well-drained substrate. The substrate should be composed primarily of peat amended with pine bark, vermiculite or perlite to provide sufficient water-holding capacity since drying out will suppress growth and flowering. Generally, a mixture of 1 part leaf mold, 1 part peat moss, 1 part sand and 2 parts loamy top soil gives good results. The pH of the substrate should be adjusted to a range of 5.8-6.5.
Repotting:
Mature African Violet plants won't need very frequent repotting. In fact by doing it often you will reduce the flowering potential as a slightly pot-bound pot is helpful in getting the blooms. Very young plants or very pot-bound mature plants will need repotting, ideally in Spring or early Summer.
Watering:
Soil moisture and proper watering are critical to your success in growing African violets. Plants can die from too much or too little water. How often to water and how much vary depending on the soil, pot and plant sizes, and environmental conditions. Keep compost moist, allowing the compost to dry out slightly between watering's. Sub-irrigation methods, such as capillary mats and ebb-and-flow, or drip irrigation are generally used. If overhead irrigation is used, apply early in the morning so that foliage can dry during the day. Foliage should not be wet overnight or spotting can result. Water temperature is critical. If irrigation water is too cold or too hot, foliar damage will occur. This is most common in Florida during the winter when irrigation water is colder. Light green or yellow spots can appear on the upper surfaces of the leaves. Deep well water is usually near 70°F and rarely causes problems, except when it is stored in hoses or irrigation lines or outdoors in fertilization tanks.
Fertilizer:
Saintpaulias have relatively low requirements for nutrients. Newly potted plants should not receive fertilizers until root growth is well established. Plants then should be fertigated using a balanced liquid fertilizer, such as N-P2O5-K2O at a ratio of 15-15-15 or 20-20-20 with nitrogen at 100-125 ppm or 1,000 lbs. N per acre annually. Micronutrients may be included in the substrate or can be included in the fertilizer program. Monitor substrate electrical conductivity (EC) at least monthly to be sure plants are not over-fertilized.
Propagation:
Older plants usually have more than one crown that's why they are easily propagated by division. After you have gently removed the plant from the pot, divide the crowns by cutting through the root ball with a sharp knife. Be careful not to destroy all the roots or to shake all the soil from the root systems.
You also can get more violets with leaf cuttings and tissue culture. When propagate using leaf cuttings, you should cut from healthy stock plants. The petiole should be trimmed, dipped into rooting hormone, and inserted into the propagation medium. The cutting instruments should be sanitized between cuts to prevent the spread of pathogens. Many different propagation media can be used including peat, peat and sand mixes, vermiculite, peat and vermiculite mixes, or commercially bagged growing mixes. High relative humidity should be provided, usually by use of a mist or fog system to maintain the leaf cuttings until rooting occurs. Cuttings should be spaced so that leaves do not touch each other and the media should not be water saturated during propagation since this favors development of pathogens, such as bacterial and fungal rots. Leaf cuttings root in about two to three weeks at 70°F. Plantlets emerge from the base of the petiole approximately six to eight weeks following root development. Many growers remove the "mother leaf" at this time to avoid shading the newly emerged plantlets. Plantlets can be fertilized with a dilute liquid fertilizer at this time. The total propagation time to obtain transplantable material (three to five leaves per crown) from leaf cuttings is approximately 14 to 16 weeks.
Very few Saintpaulia cultivars come true from seed. Sow the seeds thinly onto the surface of very fine, screened, pre-watered, level, peat substrate. Irrigate with a fine mist so that seeds will settle into the medium. Further covering is not necessary. Maintain high humidity with mist or fogging. Avoid direct watering. At 70°F media temperature, germination should take approximately 25 days.
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