If you already have a Gesneriad, such as the florist's Gloxinia, Kohleria or Achimenes, then you may know that now is the best time to divide your plant. I'm always dividing my plants because I know some may die and I hate when I lose one. My first florist's Gloxinia grew from a leaf my friend gave me after I spied her plant on her balcony. It was blooming and it had more than ten flowers, blooming at once. I was struck by its beauty and I wanted to have one too. I asked my friend how to divide it, and she said that she would give me a few leaves to place in a glass of water to root. I took those leaves and started my own plants. I was lucky that two of the leaves rooted because I'm still learning how to take good care of them and I killed one, then a few others along the way. The one I've cried the most for was this beauty, white with pink dots, a Sinningia guttata hybrid - I still can't forgive myself for letting it die! But this was part of the learning process and I've learned a lot since then.
My friend told me her plant's name was Gloxinia, but then I've found out that scientists have changed its name into Sinningia, also called Florist Gloxinia, Sinningia speciosa or Gloxinia speciosa. The easiest way to divide a sinningia is through its leaves, cuttings or pedicels after the flower is spent. A pedicel is the flower's stem. Every summer I take a few healthy leaves or pedicels from each plant and put them in a glass of water to root. Some of them don't make it and dry out, but most of them develop roots at first and then small pink tubers, while sitting in the water. It takes two to three months to develop tubers. Sometimes plantlets grow from the new formed tubers in the water, if I keep them long enough - better said, when I forget about them! If you want your sinningia cuttings, leaves or pedicels to make tubers remember to check on them more often and refill the water in the glass, if necessary, so the roots don't dry out. My advice is to put the glass in a place where you can see it every day, preferably a sunny window. The old leaf may start to dry while rooting in the water, but this is normal, no need to worry. Old leaves from cuttings also dry out while new leaves are growing.
In the fall or as soon as the roots are big enough, the new plants are ready to be planted. After planting them in pots, I water them for a month or two, so they can form tubers and resist dormancy. New leaves sprout, while the old leaf dries out. If they already have tubers, I plant and let them go dormant. When winter is close, I stop regular watering and water only a few drops once in a while. When the leaves are rooting too late in the fall, I pot them in small pot and water them regularly, all winter long, without letting them go dormant. New leaves sprout and grow until spring, when they will be ready to be repotted.
The "mother" plants usually bloom until fall when I stop watering them regularly and store the pots on the lower rack shelves in my conservatory, where is darker and a bit colder. When I was living in an apartment in the city, I used to store them in my closed balcony, where it was cold (but not freezing), so I needn't have to water them anymore starting fall. In my new home, the conservatory is like any other room and it's warm inside, so I need to water the sinningias every three or four days with a few drops of water, just to keep the tubers from drying out while they're dormant. The only gesneriads which are more drought resistant and don't need any watering during their dormancy are kohleria and achimenes.
After a few years, the Florist gloxinia's tuber will grow large, sometimes as big as the pot, so I need to divide it, otherwise the plant will stop blooming and growing as well as before. Dividing tubers is easy, just have to take the tuber out of the pot, clean away the soil on it and then cut it with a sharp knife, in as many parts as I want. I just have to make sure that each part has a few fuzzy roots on it, so they can help the tuber feed itself. I need to take very good care with the fuzzy roots and don't break them off! If the tuber has more than one crown (sprout) growing from it, I can divide it in as many parts as the number of plants.
I pot each of the tuber parts in small pots, filled with peat moss soil. This kind of soil is perfect for gesneriads growth. Nevertheless, I also fertilize them once a week after they show up new growth.
If some of the sinningias aren't sprouting together with all the others in spring, it may be a problem. This usually means the tuber is rotted, so I need to take it out of the pot and see what it is. This has happened to me a few times before and it happened this year again, with one of the Sinningia 'Empress Red'. It had no sprouts and I dug out the tuber to see how it looked. It had two tubers, one bigger and one smaller but both were rotted. They were both fleshy, black and moist inside and their roots were brown instead of white. Lucky I have another one which is already sprouting!
I'm also dividing my kohleria and achimenes, because their rhizomes are growing so many that they are almost filling the pot. I usually use this propagation method which is easier, rather than dividing them from cuttings. I take part of the soil out of the pot before or after I see the first sprouts in spring. If they have sprouts I have to be more careful and not damage them, so I prefer doing this before the sprouts appear. Only one small part of one small worm-like rhizome is enough to start a new plant. This is why I have now several kohlerias and achimenes growing in other pots, where some of these rhizomes got through, by accident, during repotting other plants in the same time with kohleria and achimenes. I just move some of the soil containing rhizomes in another pot, fill the pot with peat moss soil and wait for the plants to grow. Remember, they don't need watering until the first sprouts appear. If you want to water all winter long and have the kohleria and achimenes growing and blooming, you can do that, but it will grow leggy and you will need to trim it back anyway, so why not let them have a pause after which they will grow better and be more beautiful?
I wish you luck when dividing your Gesneriads, and Happy Gardening! Who says gardeners don't have anything to do during winter?