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A taste of spring indoors

January 12, 2007 12:50 am

R ECENT WEATHER teased us with spring tempera- tures, tricking some plants into producing a flower or two. But there are sure to be cold days ahead when some indoor color will be appreciated.

At those times it's nice to have blooming plants indoors. Consider a florist gloxinia (Sinningia speciosa ) or Cape primrose (Streptocarpus ) to bring a little spring color to the indoors.

These plants are members of the gesneriad family, pronounced either "guess-NIR-ee-ad" or "jez-NIR-ee-ad" according to the Gesneriad Society. With more than 2,500 species, this family also includes the popular African violet, lipstick plant (Aeschynanthus ), goldfish plant (Nematanthus ), flame violet (Episcia ), and Cupid's bower (Achimenes ).

Gesneriads vary greatly in plant size, shape, and flower type but a common characteristic is colorful flowers. It's because of their long-lasting colorful flowers that they can brighten up the indoors on a winter day.

Gesneriads are from tropical and subtropical regions of the world so their temperature requirements are similar to our indoor temperatures. In their native settings, they are found growing in humus-filled depressions or rock crevices, on humus-covered forest floors or on tree branches. They prefer nighttime temperatures in the 60s, and daytime temperatures in the 70s.

Like most other tropical plants, gesneriads like high humidity and require it to perform well. They prefer a 50 percent or more humidity level. Adjustments can be made indoors to help increase the humidity like setting the pot on a tray of wet pebbles or using a humidifier. Many of them make great terrarium plants because of the humidity needs. Definitely keep them out of drafts and away from heat vents.

Gesneriads can be a little picky about water. Many develop leaf spots if water that is 10 degrees colder or warmer than leaf temperature is applied to the foliage. Let the water reach room temperature first to avoid this problem. Well water with a lot of minerals or softened water can be harmful to some gesneriads. If problems develop, use distilled water. Apply water until it starts to come out of the bottom of the pot and empty the water that drains out. This helps to leach out minerals from the soil and helps prevent the build-up of soluble salts in the pot.

Though African violets are colorful plants and a favorite of many, one of my personal favorites in the same family is the florist gloxinia. It has vibrant, velvety, bell-shaped flowers and attractive green foliage. The flowers are produced above the foliage so you first notice the flower color. The plant would make a nice, and different, Valentine's Day gift. They're available in colors such as deep pink and red.

Florist gloxinia needs full sun in the winter and some shade in the summer. The soil should be kept moist but not too wet, because crown rot can develop. As its name implies, the result is rotting of the base of the plant. Florist gloxinia prefers temperatures in the upper 50s at night, and in the lower 70s during the day. Fertilize only when the plant is actively growing or flowering.

One part of caring for florist gloxinia that's a little different from other members of the gesneriad family is that it needs a rest period after blooming. Gradually reduce watering after it flowers until the stems and leaves die back. Then place the plant in a cool, dark place for two to four months for a resting period. Water occasionally until new growth emerges. Then repot it in fresh soil, place it back in the light and provide plenty of moisture. This plant can last several years with proper care.

Cape primrose is another great choice for cheerful, vibrant flowers. Between two and 12 flowers are produced on its stalks. Flowers range from 1-2 inches to more than 3 inches depending on the variety. Colors include white, pink, red and violet.

Care is relatively simple. Cape primrose likes a bright, indirectly lit south, east or west window. Keep the soil moist during active growth and flowering and let it dry out between watering at other times. It likes high humidity and is similar to the florist gloxinia for temperature and fertilizer requirements. If kept too wet or too warm the leaves will flop or get limp. If this happens keep it drier than normal and put it in a shady spot until it recovers.

To keep it looking its best, trim off leaves that turn yellow and trim back any that turn brown on the tips. Once all the flowers have died back on a stalk cut the flower stalk back. It can be repotted in late winter or spring as needed.

To determine when plants need to be repotted, examine the root system by carefully removing the plant from the pot. If the roots start growing out of the pot or are encircling the inside of the pot, it's time to repot. Use a soilless mix that is loose and porous but also has moisture-holding abilities. African violet mixes work for many in this family.

Propagating gesneriads is fairly simple and includes seeds, division, leaf and stem cuttings. Florist gloxinia is grown from seeds or from leaf or stem cuttings. Cape primrose is reproduced by dividing the plants, seeds or leaf cuttings. For more specific details, contact your local Virginia Cooperative Extension for a leaflet on plant propagation.

You can find florist gloxinias, Cape primrose and other members of the gesneriad family in florists, garden centers and some grocery florists. Try to choose the healthiest-looking plant.