Add Gesneriads To Your House Plant Collection

This week marks the beginning of the holiday season for many of us, and with shortening days and the outdoor garden winding down, it’s time to continue our gardening—but indoors.Looking for some color? Want to try gardening on a smaller scale and not have to worry about the cold? Well, maybe it’s time for you to look at a great plant family known as the gesneriads.

This entire family of plants is named in honor of the 16th century Swiss naturalist Conrad Gesner. Okay, does African violet ring a bell? Does Gloxinia sound familiar? How about Cape Primrose (Streptocarpus), Flame Violet (Episcia), or the lipstick and goldfish plants? Many of us have grown one of these or received one as a gift at one time or another, and they all belong in the large and wonderful plant family called the gesneriads.

And if you haven’t grown any of these, it’s time.

Like other plant families, this one has relatives that are both natural (species) and manmade (hybrids and clones), whose foliage can be smooth to hairy, short and rounded to long and lance-shaped, and whose flowers run the range of colors and sizes of the plant world.

Best of all, though, is that in spite of all this diversity, many plants in this family make wonderful houseplants. Even for those with very limited indoor growing space, a square foot or less can accommodate a dozen or more of the miniature African violets that are grown in pots 2 inches or less in diameter.

While it’s both hard and dangerous to try to come up with a set of guidelines for buying and growing plants in this large family, we’ll give it a go anyway.

First piece of advice: Keep it simple and buy smart. Supermarkets and discount retailers are not the place to buy these plants. Choose your plants with care, and buy only plants that you really have space for. Resist plants that are on sale; they’re on sale for a reason, and that reason isn’t because they’re the cream of the crop.

Remember also that plants mature, and you rarely purchase a mature plant. They’ll need space—more space than the size of the pot you buy them in.

And try to keep your plants named. No, not Sally or Tim or Ruby. Most plants come with tags that have both a common name and botanical name on them. When the day comes that you need to look up Epicscia, Columnea or Petrocosmea to find out what temperature ranges they prefer, only the botanical or scientific name will do.

Now, truth be told, gesneriads do very well in greenhouses. But from my own experiences, I know that there are more than enough varieties that do well in a home or apartment with average heat and humidity. Many of these plants can be grown near a windowsill, but some larger varieties will do best in hanging baskets where they can cascade, or atop a plant stand.

Many of these plants also do incredibly well under artificial light, which can open up all kinds of possibilities. In fact, many greenhouses grow all their African violets and streps on multi-tiered light stands. You’ll be amazed at how many plants you can fit under a 2- or 4-foot grow light, and what a change it can make to a room at very little cost.

Again, as a general rule, these plants, except for the alpine varieties, thrive in a temperature range from 68 to 80 degrees, so long as there’s good air circulation. Most prefer humidity over 50 percent, but if this is a problem you can easily create microclimates by setting the plants in trays or saucers filled with gravel or small stones, and keeping the stones constantly wet without letting the water touch the pots.

For the most part, these plants will thrive at a temperature and humidity in the winter that is also best for your comfort, as well as for any furniture or artwork that you may have.

Remember that some of these plants have dormant periods. A good example is the gloxinia, which most people throw out when the plant begins to fade. It’s only going dormant and, had it only been allowed to rest for a few months, then given a little water, as if by magic it would rise from the … living.

Soil, however, is a touchy subject and often debated among amateur and professional gesneriad growers, as there are numerous preferences and many soil mixes that work. Again, if you are looking to make life simple, just buy a potting soil that’s advertised or labeled for African violets. This soil will be loose and well drained and will probably contain materials like perlite and charcoal that will allow plenty of air around the roots.

Like most plants, this family will thrive with a fairly consistent regimen of care, which includes a well-balanced fertilizer. There are many products available, including those specifically formulated for African violets. Some growers like to rotate different fertilizers, depending on the time of year or the flowering habit of the plant, but you can use a balanced fertilizer, which will have numbers in the ration of 1:1:1, such as 10-10-10 or 20-20-20.

Or you can opt for a fertilizer that is higher in phosphorus (the middle number) to encourage blooms at flowering time—and here you are looking for a ratio of 1:2:1, such as 5-10-5 or 15-30-15. Every brand will have slight variations and hype, but all you need to do is watch the numbers.

Many of the fertilizers will be chemical-based, and this can lead to a buildup of fertilizer salts and acidity. One way to avoid this is to look for organic fertilizers. These generally are of lower analysis but not lower quality.

Watering can be done in a variety of ways. Mats can be used, as can wicks, or the good old pot-by-pot method. There are two hard and fast rules, though: First, don’t get the foliage wet, especially on the violets; and, second, don’t let the soil get soggy nor let it dry out.

Remember also that with an over-potted or newly potted plant, the soil will absorb much more moisture than the plant can use, and this results in wet soil—and dead plants.

Pests and diseases can be kept to a bare minimum if you buy healthy plants, keep the foliage dry, don’t let the plants touch each other, and scout your plants. Scouting is critical, as it allows you to discover a single pest before it becomes an infestation. This means knowing how to identify a mealy bug, a fungus gnat, an aphid, scale and a spider mite.

Now, you may never, ever have any of these critters. But if you know what they look like, what part of the plant they might live in or on, and look for them regularly, they’ll never get out of control and take over. And if one or two sneak in, there are very safe organic remedies, such as pyrethrum sprays and insecticidal soap.

So, all that said and done, here’s a short list of some of the family members. You can look up their pictures in a gardening book, online or find the plants at a local greenhouse or garden center: Aeschynanthus (lipstick plant), Alsobia, Chirita, Codonanthe, Columnea, Episcia (flame violet), Nemathanthus, Petrocosmea, Saintpaulia (African violet), Sinningia (Gloxinia), Streptocarpus (Cape primrose) and many, many more.

For more information on gesneriads, as well as great pictures, check out aggs.org, and you’ll tap into a great resource. And if you want to start a collection, there’s no better place to start than logees.com.

Once you’re hooked, you’ll also find out that propagating these plants can be as fascinating a hobby and avocation as collecting them.

Lots of opportunity to keep growing!