Gloxinia bulbs usually become available in garden centres in late winter, so that they can be planted to produce bloom from late May until well into the summer. These tubers can be kept over from year to year, and in fact there are reports of 50-year-old tubers still being in the possession of their owners – remarkable plants indeed.
Gloxinias are tropical plants that originate from the rainforests of Brazil. They have satiny, trumpet-shaped flowers which resemble bells turned upward and are borne on sturdy stems that support the flowers well above the foliage. The leaves are lush and velvety. They come in a wide variety of colours, from the richest royal purple to luxurious dark red, but they also are available in more pastel colours such as soft pink and pure white. Many gloxinia blooms have white edgings or throats of a contrasting colour.
After purchasing a gloxinia tuber, it should be planted in a six-inch pot in moist soilless mix. The pot should have some drainage material placed in the bottom as these plants insist on excellent drainage. A coffee filter or piece of paper towel will prevent the potting mix from getting down amongst the drainage material.
A gloxinia tuber is planted concave or stem side up and is covered with about two centimetres of the planting medium. The tubers are prone to rot at this stage so they must be watered sparingly until growth appears. I often dampen the planting medium with a solution of No-damp and also briefly soak the tuber in such a solution before I plant it. This will deter rot. It is best not to fertilize a newly planted tuber for six weeks.
Locate the planted gloxinia tuber in a bright, warm spot. Gloxinias appreciate bright light and moderately warm temperatures, and are good candidates for an indoor light garden, although the foliage must be kept well away from the fluorescent tubes because they will be scorched if they are allowed to touch the hot tubes.
Although gloxinias are relatively easy to grow, two common problems often occur: either a gloxinia’s growth becomes leggy or it fails to bloom. The most common cause of both these problems is poor light. Using high-nitrogen fertilizers will also cause more leaves than flowers to be produced, so a fertilizer high in potash is recommended.
When a gloxinia has finished blooming, water should be withheld until the soil dries out and the foliage dies down naturally. Then the pot can be stored in a cool, dark place for a rest period of about three months – this is usually during the fall and early winter. The stored tuber should be checked regularly and if new growth appears, the pot should be brought out of storage, watered and allowed to develop active growth again. In a few weeks it will once more be in full bloom.
For those gardeners who enjoy propagating their own plants and like the challenge of starting new plants, gloxinias
can be propagated by seed. You must allow a couple of spent flowers to form seed pods and allow the seeds to fully mature before you harvest them if you choose to collect your own seeds. Gloxinia seed is available from some seed houses or you can save your own. The seed should be scattered on the surface of damp starting mix and then enclosed in plastic. Germination takes about four weeks.
Gloxinias also can be propagated from cuttings. Leaves, with stems trimmed to about four centimetres, can be inserted into damp soilless mix and covered with a plastic enclosure. The cuttings should root in about six weeks. Using rooting hormone and No-damp will increase the rate of success. Eventually a small tuber will develop from which a small plantlet will form. When the plantlet gets a manageable size it can be potted up and it eventually will develop into a full-size gloxinia.
If you want to enjoy the satiny blooms of a gloxinia, keep your eyes open at the garden centres for the arrival of gloxinia tubers. You will be enchanted with the beauty of these old-fashioned houseplants, and yours may become an old friend that you will keep around for years to come.
– Albert Parsons writes from Minnedosa, Manitoba