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Gloxinia Culture

THE CULTURE OF THE FLORIST'S GLOXINIA
(SINNINGIA SPECIOSA HYBRID)

by Nancy Robitaille

How many times have you seen a florist's gloxinia (sinningia) in a show?

Rarely, probably. They are large, impressive plants with spectacular blooms that will take your breath away yet few people who collect African violets grow these plants.

THEIR BEGINNINGS:

The discovery of the Gloxinia was recorded in 1785 and named in honor of P.B. Gloxin from Strassburg, Germany. Probably due to its size the plant has not appreciated immense popularity neither at that time nor in our own. This plant was introduced into England and was named Gloxinia speciosa.

Originally the plant was discovered in Brazil and the first was called G. perennis, later called Gloxinia speciosa. The species plant did not greatly resemble the hybrids we see today in florist's shops or nursery shelves. The species plant has flowers which are slipper-shaped and nod or face the leaves. Todays larger varieties look up so you can see down into their throats.

By 1825, botanists discovered that this plant had been misnamed. It was not a Gloxinia but actually a gesneriad that belonged to the genus Sinningia. In spite of this the plant is still popularly called "Gloxinia" or "Florist's Gloxinia."

The true gloxinia is Gloxinia perennis which is grown from a knotty rootstock and is similar in construction to Achimenes. G. perennis has bell-shaped flowers, the common name is "Canterbury Bells". The true gloxinia does not produce tubers.

CULTURE OF GLOXINIAS:

You may start your gloxinia collection by purchasing a tuber or the entire plant.

Tubers of most hybrids are dark brown, rounded on one side and concave on the other.

January or February are good months to start tubers. February plantings of a tuber will assure you of a large head of bloom by late May or early June. Planning for shows is not easy. Tubers may be started at any time, however.

For show plants, only one of the plantlets that develop should be allowed to continue to grow. Other growths may be taken off and planted. Plants should be placed in the center of the fluorescent bulb so that symmetry can be at its best.

SOIL FOR GLOXINIAS:

Soil mix was recommended in my research but I will not repeat these recipes since they are outdated. Growers of today use the same soil-less mix that we use for African violets.

A medium sized tuber should be potted in a four or a five inch pot. If the tuber is really large, try a six or even a seven inch pot. Fill the pot with soil until it is three-quarters full. Press the tuber into this and twist slightly. Add more soil until the tuber is covered by three-quarters. Set the pot in warm water and allow the soil to moisten.

Tubers can be started at any time but grow more slowly in winter.

LIGHT:

Gloxinias need lots of light. in order to become symmetrical. Turn pots frequently. Plants grown in light gardens do very little resting. When the bloom period is over, they may be cut back to the lowest two leaves and kept in active growth. New leaves will appear in a few days and the plant is on its way to performing again.

Flowers will stay crisp and attractive for about ten days to two weeks. They may last longer if a slightly shadier spot is found when flowering starts. A well-developed plant will have four to seven blossoms through most of a three month's season. Slipper-type flowers are more free flowering and may have twelve to fifteen or more blossoms open at the same time.

TEMPERATURE AND VENTILATION:

Gloxinias are tropical flowers from steamy jungles of Brazil so they will enjoy lots of humidity. Temperatures should range from 72 to 78 degrees F. with cooler temperatures at night of five to ten degrees.

WATERING:

Watering your plants properly insures success more than any other single factor. Tubers have a large accumulation of moisture and this allows for less watering than for African violets. Water from the top or from the bottom but try not to water directly on top of the tuber. Use warm water. Water less during the winter months.

Warm water will not harm leaves. In fact some growers take their plants to the kitchen sink every week or so for a shower with warm water. Keep wet plants away from direct sunlight.

SUMMERING GLOXINIAS:

You may safely summer your gloxinias outdoors. The pots may be plunged into the ground under a bushy shrub or other overhanging plant growth. When the plants bloom, bring them indoors to enjoy. Be very careful about insects from outdoors including those that might crawl into the bottom holes or flying insects.

When an older plant seems limp and leaves turn brown cut off all the green growth and keep soil on the dry side. Growth will resume within about a month's time.

FERTILIZER:

This issue has been debatable since, as with tulip bulbs, amaryllis, and similar tuber or bulb plants, the fertilizer is in the bulb or tuber. Some growers use small amounts of fertilizers each two weeks. Others use no extra fertilizers. Note that the growers who use no fertilizer do use products in their soil mix such as bone meal.

Today's growers use the same fertilizers and amounts as with their African violets. Fertilizers such as 20-20-20 or 15-30-15 are recommended, ¼ teaspoon to a gallon of water used at each watering is now recommended.

PROPAGATION:

Healthy tubers may be used for propagation. Smaller leaves put into a glass of water or amount of soil soon produce small tubers.

The large tuber can also increase your collection by splitting it and planting sections. Gloxinias may be compared to potatoes which are often dotted with "eyes". Each eye may be severed with part of the tuber attached. This "eye" is capable of producing a new plant.

If you are uncertain about the "eyes" of a tuber wait until they start sprouting. This green growth may be dissected from the tuber so each section contains a sprout. Each may be dusted with sulfur or Fermate and potted up. Tubers may be stored in the pots they have been growing in.

When a resting tuber begins to sprout, take out about an inch of the soil on top and replace with fresh soil. When the pot seems crowded, take out the tuber and place into a larger pot. Some tubers take up to three months to rest while others do not rest at all. Resting tubers may also be stored in a bag or container. They do need a bit of air to keep them from molding.

Leaves may be torn from the plant leaving a heel then rooted in water or soil. Smaller, younger leaves perform better than older leaves. Roots appear in about ten days. As the end of the stem begins to broaden, it is time to plant the leaf if you have placed it in water. From six weeks to two months "mouse ears" may be seen.

Leaves can also be used in propagation like those of Rex begonia. This procedure is to sever the veins of a leaf, place the leaf face up on soil-less medium and cover the end of the stem with the medium. The leaf should be weighted down with pebbles. Provide humidity with a plastic sack. Provide some ventilation.

The leaf stem may also be split in two then planted in soil or water.

Gloxinias may be propagated with seeds. Gloxinia seeds are tiny (800,000 per ounce). Plants produced from seed usually do not have the strength to grow the next year because the newly formed corms are too small to thrive.

PESTS AND DISEASES:

Gloxinias are less susceptible to pests than many other plants. However, they may still be affected by most pests in the African violet army. Aphids, cyclamen mites, mealy bugs, springtails, static buds, and thrips may be found when growing these plants.

Gloxinias may be affected with bud blast, chlorosis, flower malformation, leaf curl, tuber rot, and wilt.

GLOXINIA HYBRIDS:

Buell nurseries seems to have hybridized most of the named gloxinia hybrids. Since their greenhouses are no longer open to the public, the grower must search in local greenhouses for unnamed varieties. The hybridizers of this beautiful plant have not recorded much information about their hybrids. Many have not even been formally named. Following are some named hybrids you may be able to find.

  • EMPEROR FREDERICK—Heavy scarlet with pearly margins.

  • EMPEROR WILLIAM—Deep pansy-purple with heavy white margin.

  • ETOILE DE FEU (STAR OF FIRE)—Sparkling cardinal-red flowers.

  • GLOXINIA CRASSIFOLIA—M. Rossiad, hybridizer 1870. Plants have rounded, velvety, thick leaves with plump short buds, large solid flowers, very wide at the mouth but with a narrow tube. Colors range through the blues and shade into rose.

  • MONT BLANC—Bright, snowy white, with little or no ruffling.

  • MONTERAY ROSE—deep glowing pink.

  • PANZER BEAUTY—Solid red flowers with wavy margins. This is an excellent bloomer and the parent of many new hybrids.

  • QUEEN WILHELMINA—A lovely and unusual combination of dainty pink with an irridescent violet sheen.

  • SWITZERLAND—Shining scarlet-cerise with a white ruffled edge, throat well flared.

  • WATERLOO—an international favorite, flowers are bright scarlet with margins deeply ruffled.

  • BLUE CHIPS—deep blue double flowers on a compact plant.

  • JACK O' DIAMONDS—double scarlet with white edging.

  • QUEEN OF HEARTS—large double rose-pink.

  • SINCERELY—a named hybrid by Peggie Schulz, rose-red slipper with white edge.

  • WHITE KNIGHT—pure white.

The Albert Buell hybrids include an entire strain of extra large gloxinias most with ruffled petals. The color range is wide including soft pinks, honey-blends, frosty orchids, near-blues and heavy whites.

It is unlikely that you have ever seen a gloxinia (sinningia) in a club show. Maybe yours should be the first!