Jennifer Schultz Nelson
Extension Educator, Horticulture
If spring fever has struck your household but your soil is a bit too wet to work, consider starting tender bulbs and tubers indoors to satisfy that itch to garden. Gloxinia is a great choice, and you may actually prefer to grow it indoors as a houseplant.
Gloxinias belong to a large group of plants called gesneriads. Maybe you've never heard the term gesneriads, but I would guess that you are very familiar with one member of this group, the African Violet. There are over 2,500 different species of plants in the gesneriad family. Most come from tropical regions of the world, and show extreme diversity in flower and foliage size, color and form.
The name gloxinia is misleading. Originally, this plant was included along with many others in the genus Gloxinia. Later, botanists reconsidered their assignment and placed this plant in the genus Sinningia, named after Wilhelm Sinning, a German botanist that worked at hybridizing this plant in the early 1900's. The name gloxinia was firmly etched in people's minds though, so they are still referred to as gloxinia by many people. Sometimes the distinction Florist Gloxinia is used to distinguish this plant from the true genus Gloxinia.
There are about forty or fifty species of Florist Gloxinia, plus countless hybrids. They all originate from Central and South America. Gloxinia are primarily grown for their spectacular flowers, typically very large, tubular shaped and velvety with a ruffled edge. Colors include white, pink, salmon, orange, red, blue and violet. Double as well as scented hybrids have also been developed.
Caring for your gloxinia is much like caring for an African Violet. They prefer moderate temperatures in the home, ranging from about 65 to 75 degrees Farenheit. Just like a lot of us, they like their evenings to be cool, preferably about 10 degrees less than their daytime temperature. Bright indirect light is the ideal, as well as high humidity.
Like African Violets, gloxinia can be fussy about watering. They need to be kept moist, but not overly so. They do not like water on their leaves, and overwatering is a sure-fire way to cause flower buds to drop, or at worst, sentence a gloxinia to an early death. Cold water will cause leaf spotting. The best way to assure proper watering is to water from the bottom, much like an African Violet. Fertilizer may be applied while watering, but preferably diluted to one tenth or one quarter of the concentration recommended on the label.
Unlike the African Violet, the gloxinia grows from an underground tuber, essentially a modified stem much like a potato. It may also be propagated by seed or leaf cuttings, making it very user-friendly for home plant propagating. Typically gloxinias are sold as gift plants in full bloom, but you can purchase the tubers ready to be potted up. I am trying this for the first time this year, and have my fingers crossed that I will see flowers this summer. There were tiny sprouts on the tubers when I planted them, so I guess that is a good sign.
Gloxinias are also unique because they require a rest period after flowering. Flowering may last up to two months, but after that the plant must be allowed to die back and have a dry rest period of anywhere from six to nine weeks. After the rest period, the tubers should be replanted in fresh potting mix, and soon a new plant should emerge, ready to flower again.
Probably the most complicated part of caring for gloxinias is the rest period. I gave my mom a gloxinia two years ago along with printed instructions on caring for it. She was doubtful that she would have any success overwintering her gloxinia, and initially didn't want to keep the plant, but I insisted she could do it. Much to her surprise, she was very successful at resurrecting her gloxinia after its winter rest period. Sometimes we want to stick with plants we know, and can miss out on some of the beautiful flowers nature has to offer. If you see gloxinia for sale this spring, give one a try. Maybe, like my mom, your thumb is greener than you thought.