True gloxinias, charming plants for window gardens, the home greenhouse, or protected shady spots outdoors in the summer, may start from tubers, young plants, leaf cuttings, or seeds.
During the spring months, seeds will sprout quickly to develop into large enough plants to transplant and then produce their first flowers, often in five months.
The tiny, spherical, dark brown seeds should be sprinkled thinly on a soil mixture that has been finely screened.
Albert Buell, a well-known gloxinia hybridizer, advocates a light sprinkling of screened sphagnum moss over the newly planted seeds.
The next step is to place a pane of glass over the container to conserve moisture, then set it in a warm, shady place, and as soon as the seed begins to germinate (about 10 days), move the container to receive the morning sunlight.
Also, remove the glass cover for a few hours each day until the plants are gradually hardened off and will no longer need the glass cover.
However, never allow them to become dry, and as soon as they are large enough to handle with ease, transplant them to regular gloxinia potting soil in flats or individual pots.
Gloxinia From Leaf Cuttings
Growing gloxinias from leaf cuttings makes for pleasant window gardening. Select green, robust leaves while the plant is still in bloom or bud.
Sever the leaves as close to the plant’s main stem as possible, where the leaf stems are hard, and insert in a mixture of sand and peat moss or vermiculite.
Or, if you prefer, leaf cuttings will root easily in a glass of water. In about two months, well-formed tubers will appear at the base of the leaf stems.
If you root gloxinia leaves in vermiculite or peat moss and sand, remember to water them at least once a week after the leaves die.
When they show signs of sprouting, remove them to 4- or 5-inch pots of soil. Cuttings always come true to color.
Gloxinia From Tubers
Growing gloxinias from tubers is the easiest method of all. Simply set dormant tubers on moistened sphagnum moss, partially sterilized sand, vermiculite, or some commercially prepared soil mixture.
Or you can plant them directly in a 4-inch pot of soil. Then, set in a warm place and water slightly until growth appears.
When leaves spread apart, transplant them into individual pots and place them in an east or south window.
You may also buy young seedlings in 2 ½” inch containers. Pot these as you would tubers, and they will produce blossoms in three months. This method is the easiest for the beginner.
After the first crop of blooms, cut the old growth off, leaving the last two leaves. New growth will appear, and you will get another crop of blooms, not as many or large as the first, but still worthwhile.
After the second crop of bloom, do not try for a third, but give the tuber a rest.
Dormant Gloxinias
Gloxinias sometimes refuse to go dormant. They are unpredictable; some rest for a week, others for three months. However, the bulk of the hybrids require little, if any, rest.
After the plant has ceased flowering, cut it back to the last two leaves and decrease the amount of water.
If new shoots spring up in a week or two, the plant will not need rest and may favor you with more flowers.
Tubers can be stored in the pots they grow by placing them in a basement or other storage quarters where the temperature is about 50° to 55° degrees Fahrenheit. Sprinkle the soil with water once a week to help keep the tubers firm and plump.
If some sprout, and you do not have time to plant them, it is better to remove the sprouts and, if possible, find a cooler storage place than to let them grow spindly in the dark.
The window gardener will likely have willowy gloxinias if they do not have enough light. If you grow them that way, give them more sunlight or boost them closer to the fluorescent lights.
You can have well-shaped specimens by placing them a few inches from the lights while they are growing, then lowering them when they come into bloom.
Control Pest and Disease
A lack of diseases and pests has helped to make gloxinias popular. Tiny, black, thread-like thrips will take a devastating toll if not arrested.
These leave reddish excrement on stems and the undersides of leaves. To eradicate the use of spray-type insecticide bombs made especially for house plants.
Gloxinia Tuber Bacteria
Tuber bacteria will likely set in and ruin dormant tubers if left in a soggy, wet condition.
Occasionally, a gloxinia that seems to be in perfect condition, even in full bloom, will suddenly wilt, and close examination will show that black rot has enveloped the tuber and started up the stems of the plant, cutting off all food.
A light, well-aerated soil, rich in organic matter, is likely to avoid this rot but is troubled with it, cutting off the leaves or top growth that is not infected. Root the salvaged portions and destroy rotted parts.
Keep Water off Buds
Spilling water on the buds and allowing them to remain inside the sepals overnight will likely rot them.
Lack of humidity is another problem. In this case, set the pots on moist sand and peat moss trays. If you have only a few large plants, set their pots inside a larger container, packing moist sphagnum moss between the pots.
Not enough water, or too much, will cause buds to dry up before opening. Placing a plant in full bloom in hot sunshine will cause the blossoms to Wilt badly and shorten their endurance.
The ideal growing temperature is from 62° to 85° degrees Fahrenheit, and a few degrees below or above are not harmful.
Equal parts of peat moss, leaf mold, garden loam, and sand make a standard growing mixture. There are packaged mixtures prepared especially for gloxinias, handy when one has but a few tubers.
Pauline Kuntz of Iowa, who grows her gloxinias and other tropical plants in a “basement greenhouse” under fluorescent lights, gives this hint for soil mixtures: “The soil mixture that I have found best for genseriads and allied plants is very light and porous.
This allows plenty of aeration for the roots, thus ensuring fast, sturdy growth. A mixture of about 1/3 peat moss, 1/3 sand, charcoal, sponge rock, and the remaining 1/3 of well-rotted manure or very rich soil containing manure grows my plants.
To this mixture, I add superphosphate, about ½ teaspoon, to a 3-inch pot. This potting mixture never requires any other fertilizing and gives me fast-growing plants and prolific bloom.”
North Exposure
Nothing can compare with gloxinias for a window box with a north or northeastern exposure.
Bedding in shaded, protected spots is excellent, and if you live in a very warm climate, where it might be hard to keep them in good condition indoors, they will luxuriate outdoors from late spring until fall.
The true species of gloxinias are always charmingly delightful. Sinningia Regina and S. macrophylla (Brazilian gloxinia) sport beautiful reddish leaves, veined with silver and rosy red on the undersides. They have the darkest purple, tiny slipper flowers.
S. eumorpha, formerly sold as S. maximiliana, has delightfully shaped leaves and flowers. Small, fat, cream-colored slippers rise above the darkest green, slick, heart-shaped leaves that are evenly scalloped with reddish undersides.
This species has recently become the parent of a bi-generic hybrid, the rosy-flowered “Gloxinera rosea.”
The pollen parent was another gesneriad, Rechsteineria cardinalis (See December 1954, Horticulture).
Slipper Types
The more popular slippers, derivatives of Sinningia speciosa, come mostly in variations of blue, purple, and pink.
By crossing these with the bold upright hybrids, we now have large-flowered slippers as striking as any gloxinia you have ever seen!
In fact, at the Gloxinia Show in Kansas City last year, the judges almost chose one as the best plant in the show.
With all the hybridization going on all over the country and in Europe as well, we are wondering what we will find in the way of gloxinias by 1960.
One thing is certain — we will not only have better kinds, but also many new ones.
Furthermore, there will be thousands of new enthusiasts! And who knows, gloxinias might be the most popular window gardening and greenhouse plant of the day!
44659 by Elvin Mcdonald