Questions on: Hibiscus
Ron Smith, Horticulturist, NDSU Extension Service
Q: I bought a
hibiscus this summer and placed it outdoors. It bloomed beautifully
until I brought it in before the winter cold set in. Within a couple of
days, all the blooms and buds fell off and it hasn't bloomed since. Do
I have to wait until summer for it to flower again or can I get it to
bloom while I have it indoors? (e-mail reference)
A: The bloom and flower bud drop is a result of a change in the
environment. The environmental change usually is the drier air from
your furnace. Quite likely, the plant will rebloom for you this summer
after you place it outdoors. Unless you can provide more indoor light
and humidity right now, I doubt that it will bloom this winter.
Q: I have a hibiscus indoors for the winter. It is doing beautifully, except for being invaded by a small, white insect. The insects are on the underside of the leaves. They do fly, but are very tiny and don't look like flies. I read your response to another person about putting the plant outside in subzero temperature for 20 minutes. I did happen to put the plant outside for a while, but the temperature was in the 30s. Someone else told me to spray the leaves with soapy water. What do you suggest? Are they harmful? I have a baby in the house. (e-mail reference)
A: The material known as insecticidal soap is worth trying. It sounds like these might be whiteflies, which are difficult to control. You also can use yellow sticky traps available at local garden supply stores. The insect is attracted to the colored card, lands on it and is stuck there. If the weather forecast holds true, you might get the below-freezing temperatures you need to kill these pests, but without killing the plant. The plant probably will defoliate after the treatment, but will releaf again in a few weeks. Before you set the plant out in the cold, try the insecticidal soap/yellow sticky trap combo first to see if that gets rid of the problem.
Q: I recently repotted my hibiscus plant and moved it indoors for the winter season. However, I'm concerned because the plant is starting to look stressed. The plant has several yellow leaves, has stopped blooming and a few branches look wilted. I repotted the plant in Miracle-Gro potting soil and used a very large pot. I am concerned I chose the wrong soil. If I have, what should I do? Do you recommend mixing sand/perlite into the soil? Will this stress the plant? (e-mail reference)
A: The yellowing of leaves and leaf drop can be expected when the plant is moved from the great outdoors to an interior environment. The soil should be OK, unless you simply used garden soil from outside. Houseplants need designer soil, which is pasteurized or sterile and has been modified for optimal drainage. Having the plant in a container that does not freely drain (a hole in the bottom) could be part of the wilting problem. Also, keeping the soil too wet results in anaerobic conditions. I would suggest getting some artificial light. Run the lights about 13 hours per day. If any of the above applies, correct it as soon as possible.
Q: We recently returned from a trip to Oahu and We brought back from a trip to Oahu two packets of hibiscus branches about 3 inches in length with a couple of leaves growing from the stem. I'm at a loss as to how these should be handled and planted. At this time, we would obviously plant them indoors. I don't know whether to use soil and plant the stem vertically or lay it flat in the moss provided and then cover it with Saran wrap with a few holes in it to encourage humidity and moisture. Can you help? (e-mail reference)
A: Hibiscus easily root using a rooting compound treatment. I would make up a media of sand/peat. Stick them in the media after treating them with the rooting compound. Provide high humidity, bottom heat and consistent moisture levels for the rooting media.
Q: I love your column and read it weekly. What should I do with my hibiscus plant during the winter months? Should I keep it in a south window and continue to water or should it go to a cool room so it can rest? (Valley City, N.D.)
A: Thank you for the kind comment and for being a faithful reader! If the plant is vigorous and growing well, keep it going. If it starts to develop lethargy as far as growth, then let it dry down and place it in a cool room. Next spring, as the days begin to become noticeably longer, bring it back to the south window, cut it back and begin watering.
Q: I am hoping you can help us out with our hibiscus plants. We live in Zone 4 and have three beautiful hibiscus plants. They are planted in large 24-inch pots. In the summer months, we put the plants outside and virtually do nothing to care for them. They seem to do well and flourish. As fall approaches, we get the plants ready to bring indoors for the winter. That preparation consists of removing any cobwebs and leaves, and giving them a good shower. At first they seemed to do well (weekly watering), but as winter drags on, we hit a crisis stage in February/March. At that time, there is excessive leaf drop and what appears to be an aphid infestation (small black bumps covering the stems). At this point my wife freaks out. I have tried using Safer's insecticide soap, which dries out the bumps, but my wife thinks using the soap is actually harming the plant. We also spend hours picking the little bumps off the stems, which she thinks helps. I am hoping you could provide us with some guidance on how we should better care for our hibiscus. I have proposed trimming the plants, but my wife forbids me to touch them! (e-mail reference)
A: There are some things that you can do that will keep you on your wife's good side. When you move them outside this summer, get a systemic insecticide from a local garden center outlet. Carefully follow the directions when handling and applying. Repeat the application about seven to 10 days before bringing the plant indoors next fall. Your insect problem sounds like scale, based on your description. Instead of picking each one off that you see (this is not spending quality time with your loved one!), get some horticultural oil that can be applied without damaging the plant. This is more efficient in killing the little buggers. If applied properly, you won't miss any insects, which the two of you are bound to do using your current method. When combined, these two techniques will do a good job of getting the insect problem under control. You both need to understand that these sun-loving plants are going to be under stress as the long winter months pass. The plants are bound to decline in quality as spring slowly arrives. The addition of plant lights through the winter months will help maintain qualitative growth. I have a special note for your wife. Hibiscus plants thrive on being pruned, so pruning will not hurt them. In fact, pruning will increase flower production. If she doesn't believe you and she does me, don't feel bad because it happens all the time to husbands!
Q: I have a hibiscus plant that I really like. Can I grow another plant from cuttings off my plant? If so, how do you care for them? (e-mail reference)
A: Yes, softwood cuttings taken in early summer work easily when treated with IBA (rooting powder). You can read up on the technique by going to my Web site on home propagation techniques at www.ext.nodak.edu/extpubs/plantsci/landscap/h1257.pdf. You can download all or part of it.
Q: This spring I purchased a hibiscus plant. I repotted it into a little larger pot and set it on the south side of my house. It grew and bloomed beautifully. Since I would like to keep it for next summer, I took it in the house. The plant has continued to bloom, but when I water it, I get many yellow leaves. What is the best way to care for this plant to keep it alive? (Grafton, N.D.)
A: What worked for me is to allow the plant to go dormant with a little help from Mother Nature. After going dormant, bring it indoors and put it in the garage, where it will get cold, but not drastically. Store it that way for two months. After that, bring it indoors, cut it back to the nodes and place it in a sunny window or under some grow lights. By the time spring arrives, it will be a beautifully blooming specimen for your outdoor setting! A word of caution: Use tepid water and do not overwater during the slow winter months.
Q: I have mushrooms growing in the soil of my hibiscus plant. I move it outdoors in the summer. The mushrooms recently have grown large and are pale yellow. Do I need to throw out the plant? (e-mail reference)
A: The mushroom simply is tangible proof that the organic matter is being broken down and that the media is moist or wet. If it bothers you, pick off the mushrooms and throw them away. The mushrooms are not hurting the plant.
Q: I have a 5-year-old hibiscus. It used to flower, but now it has grown into a tree with no flowers. I have given it sunlight, a bigger pot and vitamins. What should I do? (e-mail reference)
A: Have you ever cut it back? Sometimes that is what is needed to push it to flower. Perhaps the container you moved it into is too large, so it won’t flower until it is pot-bound. Don’t make the mistake of fertilizing it too much.
Q: I have a hibiscus at my office. It has been in a south window for two years and blooms every week. It is getting leggy, but I’m afraid to mess with it because it is doing so beautifully and it was a memorial at my father’s funeral. What is the best way to trim it back without killing it? (e-mail reference)
A: Don’t be afraid to prune the plant back to the size you want. Make the cuts right above a bud or lateral branch so you don’t leave ugly stubs.
Q: A client has a hibiscus (small tree type) and is wondering what the best way is to keep it over winter. I assume that it needs to be taken inside for winter, but do you let it go dormant for the winter or try to keep it leafed out and growing inside the house? It’s growing in a large pot. (e-mail reference)
A: There are probably at least a half dozen ways to get hibiscus to make it to the next outdoor season. What I have found that worked for me, is to allow it to get nipped back with frost and then bring it into the garage where it can stay cool or cold for six to eight weeks. Then prune it back hard and bring it into a setting that gets ample light and warmth. Start watering to keep the media moist. Leaflets should break out shortly and the plant will reward the owner with a bloom or two during the long winter months if there is enough light. Give the plant a shot of fertilizer as the new growth begins.
Q: The leaves on our hibiscus are covered with some sort of white crystals that give the leaves a grainy feel when you rub your fingers across them. I’m sure they are not white flies because I never see any movement and have looked at them through a magnifying glass. They seem a bit sticky and drop down to make the floor underneath a bit sticky. Is this normal? (e-mail reference)
A: The white crystals could be some of the salts coming out of the ends of the leaves. It could be some kind of insect, but I doubt it from your description. It’s probably not because I’ve not heard of this before nor experienced it myself in growing hibiscus. If the surface can be wiped with a damp cloth, do so to clean up whatever it happens to be.
Q: I was encouraged to use a hibiscus plant as a nutrient for my hair, but I can’t find out what is in the plant that is supposed to be so nutritious. Can you tell me? (E-mail reference)
A: I am no hair care expert, but I have heard that it is used to heighten hair color, especially red hair, and give it a good sheen. I stand to be corrected by anyone who knows more about this than I do!
Q: I live in Florida and want to send a plant to a friend in North Dakota. It would need to thrive on a balcony during the warmer months and indoors the rest of the year. Any suggestions as to what might work? I mistakenly sent a Norfolk Island pine two years ago but of course it eventually died. I would like something that might bloom. (E-mail reference)
A: Try a hibiscus. They seem to make it outdoors during summer and survive indoors through winter.
Q: I have a hibiscus plant which was in constant bloom for a couple years. I read an article by a horticulturist that said I should cut it back, set it in a dark place and water infrequently to give it a rest over winter. I did that, but now I have a thriving plant that will not flower. (E-mail reference)
A: Give it more light and less fertilizer.
Q: I have a hibiscus that I thought died last summer due to the heat. I cut it back last fall just to see if it would come back. During the winter months it started getting leaves. It was doing great until yesterday. I watered it the previous evening and the next morning all the leaves were drooping. (E-mail reference)
A: If it was doing fine until you watered it, then you have nothing to worry about. Hibiscus can be a fickle plant to grow. It can give the owner fits over its health. When all is considered lost, it sometimes re-leafs and blooms! So don’t give up, even if it drops its leaves.
Q: We have a hibiscus plant in a southeast bay window. It blooms very nicely but has problems with white flies. We also have the same kind of plant in a back bedroom on the northwest side of the house. It also blooms some but it doesn't have any white flies. The temperature in the backroom is in the 60's. Does the temperature keep the white flies from invading? (Brookings, S.D.)
A: It could be, especially if it is in the lower 60's. You can try an old trick I used a few years ago to get rid of white flies but you have to be careful. Set the plant outdoors for no more than 20 minutes in sub-freezing weather but be sure the top of the pot is wrapped in aluminum foil. Then bring it back it and prune it back somewhat. The leaves will all be toasted of course, but so will the white flies. The plant will eventually re-bud, leaf-out and bloom again for you. It worked for me and I never had to use an insecticide.
Q: I purchased a double apricot hibiscus about five years ago. Much to my surprise, it bloomed this past winter where I work. Each year I bring it home and put it outside for the summer. With the exception of having repotted it this year, I haven’t changed anything else. Can you explain what happened? (Oakes, N.D.)
A: The only thing I can think of is that this was a grafted plant. Perhaps the grafted scion wood was inadvertently cut out or died, leaving the rootstock to produce the single flower.
Q: I have a hibiscus that bloomed very well all summer and fall. The last two months its leaves started turning yellow and falling off. Does it need to be fertilized? What kind of fertilizer should I use? (Valley City, N.D.)
A: Your hibiscus is attempting to go into a rest period. Allow it to do so by backing off on the watering for the next two to three months. Water only enough to keep the soil from drying out completely and keep the plant in a cool room (55 F. best). In March cut the stems back to a desirable length, move it to a sunny location and increase the watering frequency. Once new growth appears, begin fertilizing every two weeks with a high analysis potassium fertilizer. Schultz, Miracle-Gro and other quality products are on the market for your selection.
Q: I have a tree hibiscus inside for the winter and a few weeks ago I noticed that some of the leaves were turning yellow. I just plucked them off and thought nothing of it. As time went on I noticed no improvement no matter what I did. It had spider mites but I treated it with Shultz insecticidal soap. That took care of the mites but the leaves keep falling. Upon close inspection I see that the leaves are splotching from between the veins and epidermis and spreading in every direction. On the underside of the leave there are tiny brown specs but I don't know if that is caused by spider mites or not. This is happening to all of the leaves and I don't want to treat it until I know what it is. (E-mail reference)
A: Allow the plant to die down by reducing the watering. Keep just enough water in the soil to keep it from drying completely. Keep the plant in a cool location, then in about 6-8 weeks, cut it back, place it in a sunny window, and begin watering normally again. It should start putting out some new growth. When active growth is evident, fertilize about once a month with a houseplant fertilizer such as Schultz's or another product.
Q: What books would you recommend when looking for information on trimming, shaping and caring for trees and shrubs in this part of the United States? I would like to give it as a gift.
Also, I have tried raising hibiscus indoors by a south window. The bottom leaves always turn yellow and then fall off. I was told they like even moisture and I shouldn’t let them dry out. No matter what method of watering I try they always lose the bottom leaves. I do fertilize every few weeks with a general fertilizer like Miracle-Gro. (E-mail reference, S.D.)
A: I only know of one bookstore so you will just have to explore on your own what is there, as pruning is both an art and science that is more often learned by the school of hard knocks. A good rule of thumb with any pruning is like in cutting lumber, measure twice, cut once. Try to visualize what the tree or shrub will look like when the branch(es) is removed, and certainly have a mental image of what you want the finished product to look like after you are done pruning, otherwise you'll go too far. The hibiscus would probably benefit from a dormancy period. Allow the plant to dry and drop leaves, keeping it barely moist for about 6 - 8 weeks. Then move it to a warm, bright location with some direct sunlight daily, and begin watering heavier, allowing only the top one-half inch of soil to dry. Fertilize only during active periods of growth.
Q: I have over a dozen hibiscus that have been inside in winter and outside on the deck in summer for several years. Last spring I noticed that one plant wasn't blooming, so I pruned it severely. When I brought it in this fall it had grown out again but still did not bloom while the rest bloomed profusely. What happened? I don't have enough south windows for all my geraniums. If I were to use a four foot fluorescent grow light, how high above the plants should it be? (Brookings, S.D.)
A: No idea why the one didn't bloom. As for the fluorescent light, keep it about 12 inches above the top of the plants.
Q: I have a perennial outside hibiscus plant that I've had for years. This year it has seed pods on it that are full of seeds. If I plant the seeds, will they bloom similar to the parent plant? (Colome, S.D.)
A: They certainly should, but I cannot tell you what treatment the seeds need, since most propagation is done asexually by cuttings, air layering, or mounding.
Q: I purchased a hibiscus this spring and put it in a large planter on the deck. It was beautiful! Can I keep it in the house through the winter? I am hoping not so much to have a winter houseplant, but to have a healthy, strong hibiscus to return to the deck next spring. I have a cool basement with very little light and a garage that will get to freezing temps. I have rooms in the house with west-facing windows. Some rooms I keep at average temps and one I keep cooler. Can you give me any tips on how to over-winter this plant? Also, should I cut it back? If so, should I do it now or in the spring? Also, I planted two Russian cypress this spring. Through the dry summer I kept them well-watered and they seemed to do okay. The rains finally came in mid-August and all seemed fine. Near the end of October, they began to get a brownish look and now are completely brown with a very slight red tint. The plant is not brittle, just brown. There is a Blue Star Juniper a couple feet away that looks just fine. Is this normal for the cypress to turn brown or is there a problem? They are planted in well drained, fairly fertile soil and in full sun. My last question, do you have a Web site that has an accumulation of the questions you have been asked? I am an avid gardener, but am in the process of landscaping around a new house. I would appreciate all the information I can get. (Lesterville, S.D.)
A: Based on where you live, I would suggest wintering the hibiscus in the garage. The root system is what you need to be concerned with. If it appears that the temps will get below 0 in your garage, then you'd better bring it in for the night. Russian cypress is better known as microbiota decussata - Russian arborvitae. And yes, the brown and reddish coloration is normal going into the winter months. You have selected a little used beauty for your landscape and are to be congratulated for doing so. I'm sure you will be the envy of the neighborhood in years to come. Enjoy! Past questions and answers can be found at: http://www.ext.nodak.edu/extnews/hortiscope/contents.htm.
Q: I have a hibiscus that I recently repotted. It was doing great for about three weeks and now the leaves are wilted and some are turning hard and brittle. Some of the edges are starting to turn brown. The soil is wet almost to the extent of over-wet. I watered about four days ago and the leaves remain wilted. When I did water, some ended up in the saucer at the bottom of the pot. What can I do? If it is over-watered, why are some of the leaves drying up and falling off? (E-mail reference)
A: You could be witnessing what is known as physiological wilt. This is essentially the same as wilt caused by a lack of water reaching the aerial part of the plant due to a weather-caused drought. It is now being caused by a lack of water from anaerobic conditions -- keeping the soil so wet that the root system can’t get air. These plants go into a rest period during the winter and should only be watered to the point of preventing the soil from drying out. So let it dry up. If the plant still has life in the stems, it should releaf for you. Check the cambium with your thumbnail and if it is green, the plant has a chance. If it is yellowish or brown, it is over! Always pour off the excess water in the saucer.
Q: On our perennial hibiscus, a few fringes of the leaves are curling up and in. I can't see any kind if insects. As of now they are not changing color. The plants are loaded with buds. Do you have any guesses? (E-mail reference)
A: Curling leaves are usually an indication of drought or salt stress. I suggest attempting to keep them well hydrated with high quality water.
Q: My mom has a hibiscus plant and it has been doing really well, but now some leaves are turning yellow, would you know why? It sits in the south picture window and gets plenty of sun, she waters it every other day. She takes really good care of it. (Beach, N.D.)
A: Only a guess that it may be attempting to enter into an early two to three month rest period. She might try backing off on the watering, allowing the plant to defoliate, and water only enough to keep the soil from drying out. If it is still putting out new growth, have her fertilize with a houseplant material to see if that improves things.
Q: Is Christmas cactus poisonous to pets, specifically cats? We recently purchased a Christmas cactus plant and our cats are attempting to eat it. I know that Poinsettia is poisonous to cats. (E-mail reference)
A: Poisonous, no; good to eat, also no. I would still keep the cats away from the plant, as there might be some residue from pesticide applications that could make them sick. I suggest visiting a local pet store and purchasing some grass seed or some grass that has already sprouted. That they can eat, but it acts as a purgative on them in most cases, so be prepared to clean something up!
Q: I have a hibiscus plant that needs pruning. How much can I take off without killing the plant? It's about 4 feet tall, has blossomed twice while on the patio and twice inside, but it's pretty large and is obstructing the view of the TV. (E-mail reference)
A: The hibiscus can be cut back to suit your needs. They are generally vigorous plants and will produce new growth shortly, although not in the robust manner that is experienced in spring and summer seasons.
Q: We have two hardy hibiscus plant that were planted this spring in north central Kansas, have grown and are blooming, but the leaves are curling both upward and downward right from the beginning of the growth. Some of the buds also drop off before blooming. We feed them miracle grow monthly and water as needed. Do you have any suggestions? (E-mail reference, Kansas)
A: Hibiscus are somewhat temperamental and are not on my list of favorite plants. Although they are touted as pH adaptable, it could be the high pH of your soil that is causing the leaf curl; possibly the hot, dry, Kansas air is causing bud drop. Try adding sphagnum peat moss to the soil to sustain an even moisture regime and depress the pH somewhat; try spray misting the buds to see if that reduces bud drop. Where these plants thrive, they can look great! Also, remember to prune hard next spring to encourage large blooms and fresh growth.
Q: I have two large hibiscus (one double and one single). Both are full of buds and blooms and have been all winter, but they are getting very large and I want to trim them back. I have been waiting for them to quit blooming but that doesn't seem to be happening. Do I cut them back anyway? They are in the south window and I water them when leaves start to droop. (E-mail reference, Sanborn, N.D.)
A: Yes, go ahead and prune them back to size. Congratulations on getting them to flower so continuously! You must have found the ideal location for them to have an ideal life.
Q: You have mentioned using insecticide soap to wipe leaves. Where do I find it, and what is its name? I thought the problem with my house plant (can’t think of the name!) is that the leaves nearly fell off when we were on holiday in November because Granny forgot to water, but the new leaves curl and turn brown. I checked the branches and found empty brown shells about half the size of a dehydrated lady bug. I sprayed and last week made up a systemic bug killer. I think it has helped, but the smell in the house is awful. I won't do that again! I am sorry about the name. I just can't get my brain to spit it out. It is the tropical plant you see used in Hawaii in the women's hair. Mine is not in bush form but like a rose tree.
A: Probably a hibiscus plant. I would stay away from systemics if you have to be in the same room with the plant for any length of time. Anything that smells that bad cannot be good for you. Insecticidal soap is widely available, as "insecticidal soap." It is harmless to us but causes desiccation to the insects that it is sprayed up. They in essence dry up. The "bug" sounds like aphids. Something must have come along and sucked the living juice out of them. If my guess is correct about it being a hibiscus, leaf drop and slow-down in growth is normal leading into a "dry" dormancy. Allow it to happen, prune it back heavily after a few weeks of rest, water and fertilize, give it plenty of light, and enjoy! Summer it outdoors if you can.
Q: I have a new problem with my beloved hibiscus. It is now wilting. Is it just shock from refreshing the soil last week? The soil is moist but not soggy. Could it be from leaving the Sevin dust on too long? I rinsed all the leaves today to get the dust off. (E-mail reference, Wichita, Kan.)
A: Most likely transplant shock. Cover the plant with a clear plastic bag, supported by bamboo stakes, after you have misted the foliage with distilled water. The wilted leaves may fall off, or they may rehydrate, depending on whether or not an abscission layer has formed. Either way, the plant will eventually recover. Just don't let it roast in direct sunlight with the bag over it!
Q: I have a tropical hibiscus plant that I purchased nearly five years ago. It was in a 6-inch pot but bloomed beautifully for about a couple of months. My cats ate it one day until there wasn't much left. I cut it back and hoped for the best. It has since grown back beautifully but has never bloomed since. I have put it outside during the summer and pruned it several times since. About two years ago I transplanted into a 10-inch pot. Last spring my mother, who used to work in a green house, cut it back drastically to help. It has grown back and continues to grow even during the winter but still doesn't bloom. It is on a table directly in front of a south facing window and is growing but never even produces buds. At the moment it is infested with white flies, so today I am going to try to wash those off. I read somewhere that blooms only appear on new growth not woody growth. Could I be pruning too much? My husband thinks I should get rid of it and buy a new one, but I am attached to it and just don't want to give up. (E-mail reference, Wichita, Kan.)
A: My best guess is that your hibiscus is not getting enough direct sunlight. It should be placed in a west or south window that gets direct sunlight at least some part of the day. It benefits the hibiscus to summer it outdoors as well. My next thought is the fertility. You need to be using a houseplant fertilizer that is high in phosphorus and potassium and lower in nitrogen. Hibiscus grow fast anyway, and anything with a high N content could almost put it in orbit growth-wise. The plant can be pruned heavily, as it does flower on new growth, not the old. Get rid of the bugs by spraying with Insecticidal soap. That will knock them out and will not harm you or your family.
Q: I have a double red hibiscus that has gotten very leggy. It is in a 10-inch pot in the south window. I know I should cut it mback, but it won't quit blooming. And the leaves are turning yellow on the bottom half of the plant. Can I cut it back even if it has buds on all of the stems? What can I feed it to stop the yellowing? (e-mail)
A: The hibiscus needs a rest! Let it go dormant and then cut it back hard to start over again. They will typically get leggy in a household environment. Once the leaves have dropped off, cut it back and set it outside for the summer. Water it when the rain is insufficient, fertilize once a month with a complete fertilizer and you will be rewarded with some more beautiful blooms.
Q: What is causing the yellowing and dropping of the leaves on my hibiscus at this time? I noticed the same thing happening with other people's plants also. (Fargo, N.D., e-mail)
A: A number of things contribute to leaf drop of hibiscus and other houseplants at this time of year: low light, dry air, alterations in watering and natural resting cycles. Keep in mind that houseplants mostly originate in the tropics, which sees wet/dry cycles. Our summer/winter cycles have about the same effect--with our interior air down to about 10 percent relative humidity in the winter and the footcandle intensity of the sun's light generally less than 75. It's no wonder that we have troubles with our houseplants during this time of year.
My advice? Don't worry about it, but certainly don't overwater to compensate. Let the plant enter a resting stage and keep barely watered. Then, as spring moves in and new buds begin to swell, increase watering and the light intensity, if possible, by moving your hibiscus to another location.
Q: I have two leaves from a plant with pink flowers, and I want to start the slips. Will they root in water? What kind of light do they need? How much should I water after they've been planted? Also, I have another longer leaf that I got from a friend whose plant is 45 inches tall. I replanted this leaf in a 5-gallon pail. I have it in a north window with medium sunlight. What are the names of these plants and how do I care for them? (Carrington, N.D.)
A: Your plants are, respectively, the hibiscus and the dracaena, which is commonly called the corn or dragon plant. Both plants are easily propagated: the hibiscus via woody cuttings taken in February when it normally gets pruned prior to a new surge of growth and the corn plant via cuttings laid horizontally in sphagnum peat moss.
For more information, refer to these publications available from the NDSU Extension Service: "Home Propagation Techniques" (NCR274) and "Interior Plantscaping with Large Houseplants" (H-1123).
Q: I have been given a large hibiscus plant that summered outdoors. I've since brought it indoors--only to discover that it had small white aphids on the leaves that fly when a leaf is disturbed. Over the course of eight weeks, I washed it with a garden hose and nozzle, sprayed it with Sevin and Malathion, cut the plant back to 6 inches and re-sprayed, and changed the top soil--only to have the aphids re-appear.
My last attempt was to put the plant in a garbage bag and use a Raid concentrated fogger. After 10 days, I'm not seeing any bugs. Was my spray not effective or can it be reinfected from the carpet under the plant? (Mitchell, S.D.)
A: A classical case of pesticide resistance! The whitefly species has been attacked by a host of insecticides ever since they and mankind had a difference of opinion of where they should live! You are to be congratulated for winning this battle with them. To keep re-infestation from taking place, check any other plants you may bring into your home very carefully for similar critters. Isolate new arrivals for about a week before moving them close to your hibiscus.
Q: I received a beautiful hibiscus plant, but I know nothing about caring for it. The instructions say to not over water and fertilize occasionally. What kind of fertilizer? Also, I was told that it could be set outside in the summer. Is this true? Can I just put the pot outside and should it be in full sun or partial? (Walcott, N.D.)
A: A hibiscus is a very attractive plant indeed, and Hawaii's state flower! During the winter months keep your hibiscus indoors in a location that will allow for at least some direct sunlight. Because it's in its resting period, it enjoys temps on the cool side, about 55 F (though mine is doing quite well at 65 F to 70 F). Do not fertilize it until next spring, and water it only enough during the winter to keep the soil from drying out.
In the spring, cut the branches back to within 6 inches from the base and repot the plant in a larger container, depending on its size, so that its roots don't become container bound. Fertilize it (Miracle-Gro should work fine) according to the manufacturer's recommended rate, and move it outside. For convenience sake, you can just leave it in the container. Because it is of tropical origin, a hibiscus likes warmth and sun in the summer, and it will respond to fertilizer applications.
Q: I am following all of the
directions I have heard of for
caring for my hibiscus, except the leaves are turning yellow. Is
to the soil it was originally planted in? (Wahpeton, N.D.)
A: It could be your soil is deficient in one of the chlorophyl-forming nutrients. Give it a shot of houseplant fertilizer once a month to see if that improves the appearance.
Q: I purchased a hibiscus this spring and enjoyed having it flower all summer long. Now that winter is upon us, I need some advice on how to care for it though the winter months. Should it be brought inside and placed with the other houseplants, or should it be placed in a dark basement closet for a period of time? (e-mail)
A: The hibiscus needs to be kept in a bright location, with temperatures above 55 F. You may continue to get more flowers through the winter. Cut it back hard in the spring prior to moving it back outside. That way, it will retain a compact, bushy form, rather than a lanky, open one.
Q. Could you tell me what is happening to my hibiscus plant? It still has blossoms, but the leaves are turning yellow. Also, do you know anything about the Gerbera daisy? (Valley City, N.D.)
A. The hibiscus could be short on nutrients, or it is attempting to go into a rest period--known as dormancy.
The Gerbera daisy is an easily grown pot plant with daisy-like flowers. They come in a wide range of colors and need to be kept constantly moist and occasionally misted. They can be started from seed. The cultivar Parade will produce uniform, compact flowers--a very satisfying plant to grow if you have a bright spot that gets direct sun part of the day.
Q. Can you tell me why my bouganvillea isn't blooming? I also sent in for some sub-zero hibiscus and the advertisement claims that I can leave it out and it will become a perennial bush. Is this true? (Pipestone, Minn.)
A. Bouganvillea need LOTS of sunshine and warm weather. They will bloom someday--it just requires patience. I wish I could tell you when that will happen, but I can't.
Concerning the sub-zero hibiscus, it depends on how sub-zero they are talking about! I would believe them, up to a point! To be on the safe side, I would provide some mulch coverage this fall after freeze-up.
Q. Can you tell me how to control white flies on my hibiscus? I also would like to know if you could give me some information on the best care for them. (Moorhead, Minn.)
A. I would suggest that you look for an aerosol or pump spray labeled for use of white flies at a local hardware store. Be sure to follow the directions, but it's best to spray under the leaves and on the stem to make sure you cover the areas where the white flies are more common.
Q. I would like some information on hibiscus plants. When I received my plant it had three in one pot, and I am wondering when I should repot them, and if I should split them up? (Parshall, N.D.)
A. The three plants in one pot were for maximum visual impact for retail sales purposes, not for the health of the plants.
Repot separately, cut back hard and give them a shot of Miracle-Gro. When our weather finally settles down, summer them outdoors.
Q. I think that the sample I enclosed is from a hibiscus, but I am not sure. What is wrong with it? It was blooming and all of a sudden it dried up like the enclosed branch. (Valley City, N.D.)
A. Your hibiscus is simply entering into a late dormancy from what I can tell. Simply let the plant defoliate and water just enough to keep the plant from drying out.
Cut back hard to about 9 inches around May 1 and begin normal watering, setting it in bright lightincluding some direct sunlight. Fertilize during active growth every two weeks.
Q. I have had my hibiscus plant for two years and this last winter I repotted it and enjoyed a burst of new growth of the plant. Then recently it started dropping yellow leaves. I sprayed it with insect spray, but it just got worse. I will probably lose it but still would like to know what the problem is. (Perham, Minn.)
A. I could not detect any pathogens on the sample you sent. I suspect the plant needs to go through a dormant period. Allow the plant to defoliate (don't keep watering it like you normally do), and cut the stems back to 6 inches from the base of the plant.
Summer it outdoors. After about 4 to 6 weeks of dormancy, return to normal watering. Fertilize monthly. It should recover.
Q. I have enclosed two leaves from a hibiscus I found baking in the August sun outside the local Wal-Mart last summer. It looked bushy and healthy in the sun (if a little windburned), but bringing it into my air-conditioned home, it promptly shed at least half of its leaves. I thought this might be its natural fall pattern, but I eventually had to prune back some of the bare stems so it didn't look so gangly. I also noticed some shiny spots below the new growth that finally appeared and associated these spots with what looked like pollen that previously fell from the flowers. Now this "pollen" is appearing all over the plant, but is most concentrated on the new growth. I sprayed the entire plant with soapy water, thinking I had some infestation, but the syndrome continued. I also tried some mild insecticide while it was still warm enough to do outside. No change. Please give me some clues to cure or clue too relax. The plant still looks healthy and other plants around it don't seem to be affected...yet.
Thank you for your advice last fall on my orange tree seedlings' browning leaves. Sure enough, watering them with non-softened water made the difference, and the mother tree is again producing lots of oranges. (Jamestown, N.D.)
A. Nothing to worry about! In close examination, I found salt crystal deposits in those "shiny spots," from either your water source or too much fertilizer.
If the plant is in a water-tight container or pot, this could cause salt accumulation to take place as well.
Q. I bought a hibiscus plant the summer of 1997. There were no directions. I had it on my deck on the west side of my house. It bloomed continuously. When it turned cooler, I brought it in the house and placed it in front of the patio doors. It still bloomed. I also sprayed it with an insecticide.
When it turned real cold, it stopped blooming and the leaves have died and dropped off. My questions are: Is this normal for this plant? Is it getting enough sunlight even though we have had many cloudy days?
I have always watered all my house plants and outdoor plants with tap water. We have received new rural water and it is very strong smelling and tastes of chlorine. Should I continue to water my plants with this water or would I have better results using distilled water?
Thank you. (Kulm, N.D.)
A. I will answer your last question first. Yes! No doubt about it—the distilled water will be better for the plants.
Hibiscus are sensitive to drafts, which cause leaf drop. This likely is a good thing since the plant needs a winter rest period, due mostly to the low light intensity from Mother Nature. Hibiscus are pretty tough and can provide the owners with years of beauty!
I am sorry you chose not to sign your name. I hope this letter gets to you, as I normally do not answer unsigned letters.
Q. This hibiscus plant got sprayed, but I didn't see the spray name. Will the plant die? Should I cut it off? Would some of the spray damage the soil? Should I throw it out? I would appreciate an answer and thank you very much. What spray is it? (Niagara, N.D.)
A. I have no way of knowing what was sprayed on your hibiscus plant. It didn't appear to cause any significant damage, whatever was used.
Other than some leaf spot and feeding insect damage, the foliage appears normal for this time of year. I suggest cutting it back and fertilizing with Miracle-Gro next year as the new growth is emerging. Repeat every four to six weeks.
Q: I was given three hibiscus
plants and was told that they
could be planted outdoors and all I really needed to do with them
was to water once a week and cut them
back flush to the ground in the fall. Recently, my mother gave me a huge hibiscus plant in a pot and told me to keep it in the pot and outdoors in the summer, and
indoors in the winter! This plant is much larger and greener than the plants that I have outside. Should I be keeping them inside? How large will they get? (E-mail
reference, Towanda, Kan.)
A: The hibiscus can be planted outdoors in summer and brought back in during the winter. It responds well to pruning back, like you said you did with
the others. Summering these plants outdoors seems to invigorate them to help them make it through the winter months.
Q: I bought a hardy hibiscus plant on sale at the end of a season four years ago (it was more dead than alive) and planted it in the south side of our vegetable garden. Every year it dies back to dead stalks in the winter, I cut these completely off in May, then it comes back with a vengeance in the late summer. Blossoms are about 6 to 7 inches across. Each year the same pattern, except the plant is now huge beyond belief. (Over 7 feet tall and at least as wide, many blossoms, but getting gangly.) My question is, can I divide it into more, smaller plants? How? When? I really don't want to hurt it, yet it seems I can't just let it keep coming back bigger and bigger like this. (E-mail reference, Michigan)
A: Hibiscus are not divided but are propagated by softwood cuttings in early summer. Don't worry about cutting the plant back. Do so each spring, as hard as necessary to your satisfaction to keep it in bounds. Pruning back to two or three buds will yield large flowers.
Q: We live in South Carolina and have a hibiscus plant that is doing very well. They truly do love the sunshine here. However, my wife insists that we bring it inside for the winter, while I believe it will do fine planted in the ground. Our winters here have never fallen below 25 degrees since we've lived here. I am willing to keep them watered as necessary and would love the ability to have them re-bloom in the spring and summer. So tell me, what is the best solution here? (E-mail reference, Lexington, S.C.)
A: Oh you lucky guys in the banana belt! Of course you can grow the hibiscus outdoors in your part of the country! If I were you, I would play it safe and make sure the root system was mulched going into your joke of a winter down there, just to be on the safe side, in case a sudden freeze shows up. That way you won't lose any points with your wife! Really, there should be no problem. Plant it in a sunny spot and enjoy.
Q. I have two large hibiscus plants that I have just brought in for the winter from outside. They were loaded with blossoms when I brought them in and now they have lost some of them. I am wondering if it would be okay to cut them back after they are done blooming since they have become too large to keep in the house. Also, will they be okay over the winter in a sunny room at room temperature? (Ada, Minn.)
A: Sure -- go for it! If hibiscus are not pruned back they will take over the place. And yes, they can be wintered in a sunny room at normal household temperatures. Flower bud drop is normal upon bringing the plants indoors.
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