Ron Smith, Horticulturist, NDSU Extension Service
Q: I have read several e-mail answers about gloxinias. The information was helpful and now I know why mine died. I have a tuber that I purchased and am trying to get it to grow. However, I am having trouble finding information on how to get my tuber to grow and the proper way to take care of it. How long will it take for the tuber to come up from the soil? Thank you very much in advance for any assistance you can provide. (e-mail reference)
A: If you can get yourself into a major bookstore, you will find ample books dealing with houseplants. There should be lots of information on raising and caring for gloxinias. Basically, their care is the same as that of African violets. Gloxinias need cool night temps (65 degrees) and day temperatures about 10 degrees warmer, but not beyond 80 degrees. Gloxinias will thrive under grow lights or a mixed fluorescent bulb setup.
Q: I did leaf propagation from my existing gloxinia plant and it is growing well at the moment. It is approximately 15 centimeters tall, but it looks fragile. How do I get it to be as strong as my fully-grown gloxinia plant? (e-mail reference)
A: This relative of the African violet has undergone some changes recently. It used to be the standard fare to allow the plant to dry down after blooming for three months. The tuberous root was replanted in fresh potting soil. It then regrew and flowered again, much to the delight of the owner. These days, many of the gloxinias are hybrids that are bred to bloom quickly and profusely and then die down, but without a viable tuberous root that is capable of providing the vigorous blooms that were so attractive. Your particular plant may be one of the new hybrids, so it may be lacking enough vigor to push up any decent blooms. I don't know for sure because this is the first question that I’ve had involving leaf propagation of this plant species. My best advice is to be sure the plant is getting adequate light. The light should be direct, bright sunlight (but filtered) or better yet, light from an artificial source for 12 hours a day. Keep the soil evenly moist without getting the leaves wet and fertilize with a material that is high in phosphorus, such as 10-30-10 or something similar, but definitely not high in nitrogen (the first number).
Q: My gloxinia bulbs (purchased a few months ago) were planted in pots that seemed too deep for the bulbs. After growing a few small leaves, the stalks suddenly fell, went brown and wilted. I assumed it was a fungus, so I dug the bulbs out and saw that all the roots were rotten. I cut the bulbs to see if I could save any part of the bulbs. To my surprise, the inner color of the bulb was dark brown. Is this the right color? Also, how can I tell if my other gloxinias are having root rot or are starting to go into a rest period? I may have overwatered them. Thank you very much for your valuable help! (e-mail reference)
A: Having never cut a gloxinia tuber in half, I honestly cannot say if this is the color they are supposed to be. My guess would be no because the roots had rotted. As to the rest period versus root rot, if you have the tuber in the right soil mix and pot, keeping the media just moist during the flowering period should not lead to root rot. Once past the flowering period, allow the plant to "die down" by withholding water as would happen in the plant’s natural setting in the tropics. This should last about six or more weeks. Then slightly moisten the media and continue to do so until new growth is observed.
Q: I recently bought a gloxinia to brighten up my new apartment. It came with two flowers and had several buds growing. The buds are doing well, but several days after I brought it home, the flowers fell off, leaving the stem and pistil. Is that normal? If not, what do I do to help my plant? What do I do with the stem? Will the bulb produce seeds? I’m lost and confused, so any help would be appreciated. (e-mail reference)
A: You might want to brace yourself for this news. Typically, gloxinias do not last very long as a houseplant. They make good “housewarming gifts,” but don’t expect to see them there a year after giving them! Most likely, your flowers dropped off because the plant came from a bright, high-humidity environment into a typical home or apartment environment that is lower in light intensity and humidity. Remove the spent flower petioles and enjoy the rest of the blooms. When the plant finally begins to decline, let it do so and back off on the watering. Remove the dry leaves, let the tuber dry out and store it in the same pot and soil. If you can, store it in a cool location (below 60 degrees). Next spring, repot in fresh potting soil that is high in organic matter and commence watering again. Place the plant in a bright location, but with no direct sunlight. To keep the present flowers around as long as possible, give it indirect humidity using a humidifier, but don’t mist the leaves!
Q: The leaves on my gloxinia are turning yellow and dying. You’ve said that this probably means I am overwatering and should let it dry during the winter. Since the winter is now over, is there anything I can do to try to save the plant? (e-mail reference)
A: Yes, continue to allow it to dry down. The plant doesn’t know if it is winter or spring. It is responding to a physiological need, which normally takes place in winter. All you’ve done is extend the time it has remained in leaf after it flowered. Allowing it to dry will give it the rest period needed, which is six to nine weeks. It should recover after that.
Q: I’ve read many of your readers’ questions about gloxinia and overwatering, but there is no mention of what is the right watering frequency. Should I water the plant daily or once or twice a week? (e-mail reference)
A: Water often enough to keep the media moist, but never allow it to dry out. Water every other day or twice a week, depending on the light exposure and temperature in your home. It’s a schedule everyone has to determine for themselves. Just make sure the water is at room or skin temperature and that you keep it off the foliage.
Q: I decided to see if I could start a new gloxinia after it finished blooming. I planted three leaves with roots. Out of the three, one developed into a plant. The plant had over twenty blooms, but most of the blooms never grew large enough to open. Of the few that did, the stems turned brown and fell off. From what I have read, I must have been overwatering. How often should they be watered, and what kind of light do they like? Any suggestions on how I can get the flowers to open? (e-mail reference)
A: Congratulations! You are among the brave and few who have gone this far.
Gloxinias are fussy about their water and room temperature. They don’t like many chemicals and never on the leaves. If the air temperature drops to 65 degrees or lower, reduce the watering frequency and allow the top inch to dry out before re-watering. Gloxinias need bright, but filtered light, which is probably why your plant blasted the buds instead of opening.
Try your luck again and if you get really good at it, go into business!
Q: I have two gloxinia plants that I created out of one. While I was transplanting, I noticed a big potato-like bulb at the bottom. I cut the bulb in half and planted both halves. Both have been doing quite well except that they are getting very viney and out of control. Both are still flowering as they have for the past two years. Should I do this again or should I cut the plant back? Will roots grow if I put the bend of the vine stock in some soil? I love these plants, so I don’t want to lose them. (e-mail reference)
A: You can take leaf cuttings now and they should root for you. Stick them in a sand/peat mix (50/50) or straight vermiculite or perlite. Gloxinia needs warmth, bright, but not direct light and high humidity from placing them on a tray of pebbles filled with water (especially during winter months when the air is drier). In addition to leaf propagation, they can be seed grown as well.
Q: I have two indoor gloxinias that are very leggy and almost top-heavy. The leaves are slightly curled but are still green. They get bright, indirect southern sunlight. I keep the soil moist and maintain the temperature at 65 degrees. The plants have not bloomed for a long time. Buds have appeared but then turned brown. Can I cut off the leggy stem and hope that the tubers will grow a new stem? (E-mail reference)
A: Gloxinia should be allowed to go into dormancy. Your plants may be trying to tell you that’s what they want to do. Allow them to dry down and then repot in six to eight weeks using fresh potting media. Set the tuber in a bright location but away from direct sunlight. Then start watering again using tepid water. Do not get any water on the leaves.
Q: I am looking for seed or plant sources of a double-flowered type of gloxinia or primula. (E-mail reference)
A: Sorry, I don't know of any sources. Perhaps one of my readers will know and get back to me with the information.
Q: The leaves on my beautiful gloxinia plants turn yellow as they come up. I don’t think I’m overwatering but maybe I am. (E-mail reference)
A: Most likely you are overwatering. Allow the plants to dry out and store at about 50 degrees if possible. Root the tubers in fresh, organic-rich soil this spring and start watering again. Water from the base, not the top and use only tepid water. Any water getting on the leaves will cause spot diseases. Keep the plants on a tray of pebbles saturated in water to keep the humidity high around the plant. Gloxinia is a challenging plant to grow
after it has finished the initial flowering, even for professionals, so try not to get too discouraged.
Q: I would like to start some plants from the two gloxinia plants I have. I have tried placing a leaf end and a flower end in water but it did not work. I have searched the Web and found no answers on how to re-start this beautiful plant. (E-mail reference)
A: Just to warn you, the florist gloxinia (Sinningia spp) is a tough one to propagate. Perhaps the easiest way is to take leaves and lay them flat over moistened, pasteurized potting media. Using a razor blade or sharp knife, make cuts in the veins of the leaves at several locations. Cover with clear glass or poly wrap and place in bright (but not direct) light. Make sure the cut veins are touching the soil surface. In four to six weeks plantlets will develop at the cut surfaces. Once they have reached sufficient size, remove the covering gradually, a little more each day, until completely uncovered. Then repot. Leaf cuttings will sometimes work but you have to be patient. Make your cuttings going into summer or during an active growing period. In early summer or late spring, dig up the plant, divide the rhizomes and separate by hand. Plant each segment in a small pot about an inch below the surface of the mixture. Several stems should grow from each piece of the tuber or rhizome. Remember that these plants typically enter into a dormant period during the winter months.
Q: I have made new tubers on my gloxinia with a leaf and transplanted into a pot, however it seems that I have two or three plants growing from the one tuber. Is there a way I can separate them? (E-mail reference)
A: I am assuming you mean the florist gloxinia. My references indicate that this is not one of the procedures for propagation. If you want to risk a possible sacrifice, then carefully cut a piece of the tuber with a plantlet attached. If it succeeds, then you have found another way to propagate this species.
Q. Can you tell me what kind of plant I have enclosed? I am wondering also why the leaves are turning brown? Can I start another new plant like you do with African violets? (Enderlin, N.D.)
A. Your plant looks like a gloxinia and while the African violet is related, with both in the gesneriaceae family, their methods of propagation differ significantly.
The gloxinia is beginning to die back naturally now and should be allowed to do so to complete this phase of its life. Allow the tubers to dry completely. Restart the plant by dividing the tubers and when new foliage appears, you can further propagate by taking leaf cuttings. After flowering, collect the seed and sow as well. In a few years you'll have your own gloxinia nursery!
Q. Could you please tell me how to care for a petite lily and a gloxinia? (Ryder, N.D.)
A. I am not familiar with the petite lily that you mention, but I notice in my reference that there is one that grows to only 1 foot in height—lilium pumilum. That may be the one you are making reference to. They basically need cool temperatures, bright light—but not direct sunlight—high soil moisture and humidity. As the leaves turn yellow, reduce watering. Keep the soil barely moist. Summer outdoors. I simply leave my lilies outdoors year around and get plenty of blooms on the north side of my house.
With the florist gloxinia (Sinningia) the soil needs to be kept moist, but not soggy. Fertilize with a flowering houseplant material every two weeks, and keep in bright, but indirect light, in a warm location (70 F+) free of drafts.
After flowering, the plant will go into a dormancy—so back off on the watering and allow the plant to dry down. Store at about 50 F and repot in fresh humus/compost potting soil next spring.
Q. Can you tell me how to overwinter my gloxinia plant? Does it need a winter rest, and how do I go about giving it one? (Glenfield, N.D.)
A. You are correct in your assumption of the gloxinia needing a winter rest. Simply allow the plant to dry down and store at as close to 50 F as possible. Repot the tuber in good compost in the spring. Good luck. It takes the best of home gardeners to perpetuate this beautiful houseplant.
Q. I am writing about care and culture of violets—how soon to repot, when to bring them home from florists. Why do they, after awhile, grow heavy stems, neck type? How about water? When I don't have rainwater, I have to use well water. I boil it because it does have minerals. Also, gloxinias—more or less same questions. How and when to store bulbs until early spring? (Deering, N.D.)
A. Basically African violets and gloxinias need the same care. If they become unattractive with age, they are easily propagated from leaf petiole cuttings.
You are being too fussy with the watering. Boiling does not correct a mineral problem, it tends to concentrate them. I suggest using distilled water when rainwater is not available.
Q. I recently purchased begonias and gloxinias. I believe they are perennials, but don't know if they have to be lifted in the fall. Do you have any pamphlets on what perennials do and do not have to be lifted? I'm trying to get a flower bed started with the ones that need no lifting. I would also like some literature on what to plant where in my vegetable garden. I understand that some things do not do well next to each other, but don't know which ones. Why did my Yucca plant not bloom the last year or two? It greens up nicely, but that's it. Should I have cut back the leaves last fall? Why don't the companies that package these perennials put the information I have requested on the package? All they state on the package is the planting method and whether they are annuals or perennials. Some don't even give that much information. (Orient, S.D.)
A. A lot of questions! Plants that are perennial in zone 3 or 4 (N.D. and S.D.) do not need lifting. Annuals like the gloxinias and begonias will die out if they are not brought in prior to fall frosts.
Your Yucca plant likely did not bloom either because of too much kindness or not enough direct sunlight.
The enclosed literature will help answer your other questions: "House Plants Proper Care and Problem Solving," PP-744, and "Annual and Perennial Flower Selections for North Dakota," H-322. Others may obtain these publications from any county office of the NDSU Extension Service or by calling the State Distribution Center at NDSU, (701) 231-7882.
Q. Enjoy reading your column in the Farm Forum. I have two questions for you.
No. 1: Is there a good way to "winter over" the geraniums to save them and make them bloom again next spring? I have been told to put them in a basement, but then what? Do I trim greenery down and how often do I water and how much light?
No. 2: I received a beautiful red gloxinia for Mother's Day. After the flowers fell off, the plant has become almost like a vine. How can I make it rebloom, or is it a one time bloomer? (Tyler, Minn.)
A. You ask for a "good way" to overwinter geraniums. Well, the best way is in a heated greenhouse with supplemental lighting and deionized or reverse osmosis water. Since that is not likely possible, here is the next best thing.
Place them in the basement and cut back to about 6 inches in length. Shake as much soil off the roots as possible. check them every two weeks and if they begin to shrivel, immerse in tepid water to rehydrate. Then, along about Feb. 1, pot them up and place in a sunny window. By the time the last killing frost passes, you can set out blooming geraniums. Gloxinias are members of a group of plants known as gesneriads, which include African violets. These need strong, bright light, but not direct sunlight. After flowering, allow them to dry down until the leaves turn yellow and dry up completely.
Store the plant in a cool, dry location for the winter and repot using fresh, pasteurized compost in the spring. Keep warm (70+ F) until the tuber starts producing new leaves, then resume regular watering, normal light and fertilizer practices for a nice summer of blooms.
Thank you for writing!
Q: I would appreciate any advice you can give me regarding two apparent problems with my purple-flowered gloxinia. I was given the plant about a year ago, and I transplanted it about four months ago. Some of the leaves have several brown spots on the bottom but otherwise look perfectly healthy. What are the spots? The plant has been flowering like crazy, but unlike the first set of flowers, there are several white patches or spots on the flowers now, and it doesn't look healthy at all. Have you ever heard of this problem before or do you know what it could be? (Toronto, Ontario, Canada, e-mail)
A: What I'm providing in my answer relates to the florist gloxinia--Sinningia speciosa. Gloxinias are not very forgiving of any human misgivings. They need to be kept moist--moist soil, not the foliage--with tepid water. They require high humidity, which is accomplished by placing the plant on a water-filled pebble tray. They also need bright, but indirect light--no direct sunlight. Allowing the sun's rays to reach the plant would be one of many causes of spotting on the foliage and flowers. As a sweeping generalization, it is usually the dry air of winter heating units that causes the most trouble. That, or a cold draft of air could cause the same problem. Finally, your plant could be trying to go dormant. Normally, gloxinias are purchased as tubers in the spring and brought into flower in summer. I suggest that you may want to allow your plant to go dormant, which may last four to six weeks, or just a few days. You'll know when that period is over when new shoots become visible. Then start the cycle over again.
Q: I have a beautiful gloxinia plant with several large blossoms and many buds forming, but the buds turn brown and die. What am I doing wrong? Am I overwatering? (Glen Ullin, N.D.)
A: It sounds like overwatering is the cause.