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Streptocarpus section Saintpaulia species and cultivars - African violet

Saintpaulia; photo courtesy of Flickr cc/Marimbajlamesa
Streptocarpus section Saintpaulia; photo courtesy of Flickr cc/Marimbajlamesa

This beautiful flowering plant in the Gesneriaceae family is well loved for its colorful blossoms and completely symmetrical form. Previously classified as Saintpaulia, these plants have been renamed as the Saintpaulia section of the Streptocarpus subgenus Streptocarpella after genetic analysis. Now properly called Streptocarpus, African violets continue to be called Saintpaulia by many.  They are easily grown indoors as a houseplants and bloom almost continuously with appropriate cultural care.

Cultural Requirements

Light:

African violets need as much bright light as possible, preferably an eastern or western exposure. They are also easily grown under artificial light, but will require more light than under natural conditions.

Watering:

Since African violets have tiny roots, they need to be evenly moist. Water thoroughly with tepid water either from below or above, taking care not to wet the foliage. After 15 minutes, discard all excess water that the plant has not taken back up.

Temperature:

They grow best in temperatures between 60º and 75º F during the day and 60º to 65º F at night. In summer, plants will accommodate to natural temperatures above 75º F but will cease to grow if temperatures rise near 90º F. African violets dislike cold drafts, so protect them from windowsill drafts in winter.

Humidity:

A relative humidity above 50% is preferred to successfully maintain flower production. Provide additional humidity by setting plants on saucers and placing on shallow trays filled with moistened pebbles and/or using a humidifier.

Feeding:

Feed African violets once a month in spring, summer and fall but not at all in winter. Use a dilute, liquid fertilizer made especially for African violets (10-10-5).

Transplanting:

When roots begin to grow out of the bottom of the pot, transplant into the next largest size pot. Use a fertile, well-drained soil mixture of equal parts sterilized houseplant potting soil and peat moss. At the time of transplanting, African violets can be divided and sucker growth removed to re-establish a single crown plant.

Propagation:

African violets are easily propagated by leaf cuttings. Take firm, medium-sized, healthy leaves and shorten the stalks to 1½". Place foil wrap around a glass of water and punch holes for the leaves. Place leaves through the foil into the water or plant them in a moistened rooting medium. Plants can easily be divided and transplanted by carefully pulling apart with sufficient roots attached.

Maintenance:

To keep their growth symmetrical, turn plants slightly every week. By the end of each month the plant should receive a complete 360º turn so that all the leaves receive equal amounts of light.

Special Note:

Encourage more flower buds to form by maintaining a single crown plant. Carefully remove any sucker growth as soon as it forms in the leaf axil to prevent overcrowded growth in the pot. If there is an excess of nitrogen fertilizer in the soil, too many leaves will be produced at the expense of flower formation. Remove the outer rows of the largest leaves to promote use of nitrogen and production of flowers.

Schlumbergera bridgesii - Christmas cactus

Schlumbergera bridgesii (Christmas Cactus); photo courtesy of Flickr cc/ Hans J E
Schlumbergera bridgesii (Christmas cactus); photo courtesy of Flickr cc/ Hans J E

This most striking flowering gift plant grows on trees in the tropical rain forest. It is well loved for its stunning display of brightly colored flowers that appear during the Christmas season.

Cultural Requirements

Light:

Christmas cactus prefer to grow in very bright light conditions, with at least two hours of direct winter sunlight, but no direct sun in summer.

Watering:

Water your plant thoroughly when the top few inches of soil feels completely dry. After 15 minutes, remove all excess water from the holding saucer.

Temperature:

Low night temperatures are preferable in growing Christmas cactus. To encourage Christmas cactus to set buds in autumn, keep the night temperature between 45° and 55°F. If the night temperature can be kept consistently low, flower buds will be produced regardless of day length provided.

To prevent bud drop, avoid drafts and large temperature fluctuations, keep humidity high and water correctly. Avoid moving plants from one site to another.

Humidity:

Unlike desert cacti, the jungle cacti thrive when extra humidity is provided. To achieve more moisture, stand the plants on a tray of pebbles that are kept moistened and/or use a humidifier.

Feeding:

During the growing season between March and September, Christmas cactus benefits from weekly feedings of a dilute soluble fertilizer high in potassium. When flower buds have formed, discontinue fertilizing.

Transplanting:

Christmas cactus grows best in clay pots. Re-pot only when necessary into a pot that is 1 to 1½" larger in diameter. The best soil mix is one part shredded peat moss, one part sterilized houseplant potting soil and one part sand.

Propagation:

Take 3" to 4" stem cuttings in spring or summer. Remove the cuttings from the tips down and allow them to harden off for a few days. Dip the hardened-off cuttings into rooting hormone and plant into a moistened, light, soil mix. After cuttings develop 1" to 2" roots, pot them individually into 3" pots.

Maintenance:

Remove the dead flowers after flowering and the stem tips to encourage branching and more flowers to develop at the ends of each stem.

Special Note:

Since flowering is related to day length and night temperature, the Christmas cactus can be coaxed into bloom. If the plant is kept outdoors for the summer, the cool night temperatures (50° to 55°F) of early fall will usually force buds to set before you bring it indoors. On those plants kept indoors, flower buds will form if the night temperature is maintained at 50° to 55°F. If the temperature is between 55° and 70°F, 13 hours of uninterrupted darkness will produce buds. In order to accomplish the dark periods, cover the plants with a black cloth during the night from 6pm to 7am daily. If the temperature is over 70°F, placing the plant in a totally dark closet is another way to induce flowering; in this case, the darkness must be maintained for 6 to 9 weeks.

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