Questions on: Dieffenbachia

Ron Smith, Horticulturist, NDSU Extension Service


Q: I have a dieffenbachia in my house. After this winter, the plant started to spread. However, the stem of the plant is turning yellow and the area where the stem and the soil touch is soft. What can I do? I'm worried sick. The room lacks light and during the winter, the plant was in constant low temperatures. Is there a way to save my plant? (e-mail reference)

A: From what you tell me, the plant is a loss. You can try taking cuttings from the firm parts of the stem and cut them into about 4-inch lengths. Then get some sphagnum peat moss and spread it out in a flat. Be sure to soak it in water and then wring it out. Take the stems and barely cover them in the moss. Place the cuttings in a sunny location. Mist the moss daily to keep everything moist, but not soggy. In six weeks or less, you should see some leaves coming from one of the ends. Check the other ends of the cuttings. You probably will have some roots emerging as well. Carefully lift the cuttings out and pot them in commercial potting soil. Put the pots in a sunny location and keep the media moist, but not wet. The plants will grow nicely from then on, assuming you have learned your lesson from this experience!


Q: Do you know if dieffenbachia is harmful to cats? I just received a plant and the donor said it might not be good for my cats. Any ideas? (e-mail reference)

A: If your cats eat any of the leaves, they are very liable to suffocate from the closing of their throat. I would keep it well out of reach of the cats or don't keep the plant.


Q: I've had my dieffenbachia for about a year and a half. It started as two stalks and grew two more. I moved last fall to an apartment with no light, so I have to keep the lights on during the day when I'm home. The plant gradually started producing fewer and fewer leaves until there were only a few left. I decided to bring it to work where it could get more light. It was cold and windy the day I brought it in and by the time I got to the building, all the remaining leaves had wilted. I left them on for a few days before I peeled them off. This was several weeks ago. There has been no new growth and the tops of the stalks are turning black. (e-mail reference)

A: Bury the remains and start again. There is no point in wasting time attempting to get this poor thing back to life.


Q: I have a dieffenbachia plant that has been moved and transplanted many times during its six years of life with me. The plant has large stalks, but no leaves to about the 4-foot level. Will it ever grow anything lower? It has gotten so tall and top heavy that we’ve had to stake and tie the stalks. The plant is in a deep, large pot. It has reached the second floor banister and is going strong. I have put a tiny dieffenbachia with it to make the bottom look more appealing. Please give me some advice as to what to do. (e-mail reference)

A: Cut one of the stalks back to about a 4-inch nub. This will force new growth to break from the base of the plant. This will give it a more attractive and balanced appearance. As that one fills in, you can do the same thing with the other stalks.


Q: I have a dieffenbachia that was very small when purchased. Now it is growing, but it is very skinny. How do I prune the plant so it gets big and beautiful? (e-mail reference)

A: The plant needs more light. It is unlikely that you can get this plant to convert to a thick, well-muscled plant. I would suggest doing air-layering to produce a plant. To do this, go to my Web site at http://www.ag.ndsu.edu/pubs/plantsci/landscap/h1257.pdf for instructions. You can download the entire publication for free or just read the part about air-layering.


Q: I went online tonight to find out the type of tropical plant I've had in my home for more than 10 years. I think it is a dieffenbachia. I’ve named the plant Henry. After moving into a new house, Henry began to develop some peculiar wasting in one of the trunks/branches. My mother-in-law feels that I neglect Henry. The plant has not needed much care and seems to enjoy infrequent watering. However, when the branch began to waste, I added more soil and tried to cover it up. Apparently, this was not the correct approach because the problem has moved up the branch. The leaves are still full, but droopy. Now it seems to be severing itself off several inches above this most recent wasting. Do you have any ideas? If I cut it off at the severing point and stick the top part in the soil, will it continue to live? (Grand Forks, N.D.)

A: It looks like that branch has developed a canker disease. I would suggest complete removal and disposal of the branch. I would suggest getting Henry more light from indirect sunlight or from a plant light source for 12 to 13 hours a day. The trunks should not be spindly. If your mother-in-law thinks you are neglecting the plant, ask her for suggestions. If she has some, take her up on it and see what happens.


Q: I have a dieffenbachia plant that is about 12 feet tall and appears to be quite healthy. About six months ago, I moved the plant to a larger pot to encourage more growth. It worked because there was a lot of new growth, but it has slowed considerably. I want to move to a bigger pot again. How big can I go? I want to go as big as possible without harming or killing the plant. Also, seed pods have started growing at the top. Do I cut them off? I want to keep it growing taller because I have a high ceiling. Is this a mistake? Should I cut it and grow two or three new plants? (e-mail reference)

A: Go to my Web site at: http://www.ext.nodak.edu/extnews/hortiscope/houseplnts/dffenbchia.htm for a lot of information on dieffenbachia plants. Moving the plant into a new pot often slows the growth initially. Itís sort of a shock reaction. Moving it again this soon is not recommended. Going too big will not hurt the plant any more than a normal move would, but there is an adjustment to the watering/fertilizing that often is mismanaged. This may lead to a decline of the plant or, in many cases, cause it to die. Prune off any flower pods you see developing because it slows down vegetative growth. I detect a little impatience in your note. Persevere and persist in your care of this plant and it will reward you with the size you are wishing for.


Q: I have a dieffenbachia plant that has some yellow growth coming out of the soil. I took a spoon and dug it out. The growth appears to only be on the surface. Any idea as to what it could be? (e-mail reference)

A: Nothing to worry about because it is a harmless saprophyte growing on the organic matter in the soil. Usually, it is just nondefined growth that easily can be spooned away the way you did.


Q: I have a good-sized dieffenbachia plant. The leaves on the bottom are growing upward rather than fanning out. The leaves are at a perfect height for our dog (a boxer) to walk under them and let the leaves rub over his head and back. He seems to be seriously attracted to the plant. Is there anything about the plant that could be poisonous to the dog? Iíve tried to do some research, but havenít been able to find much information. Yes, I know my dog is weird. (e-mail reference)

A: Your dog is normal, not weird. Dieffenbachia can cause death if the dog decides to take a bite out of it. The common name for this plant is ďdumbcane,Ē which does not refer to an IQ level, but the fact that all parts of the plant contain high levels of calcium oxalate. It can cause irritation and swell the dogís membrane tissues and tongue to the point of possible suffocation. Understand that this is not a poison in itself (spinach and Swiss chard also contain it to much lesser amounts). However, the concentration of this crystalline substance is very high in dieffenbachia. Perhaps your dog is smarter than you think. The dog may know intuitively what the plant contains and simply is using the leaves to gently scratch his head without ever intending to take a bite out of the leaf. Should he ever do so, get him to a veterinarian because the effects can be countered quickly with an injection.


Q: Last evening I noticed tearlike droplets on the tips of my dieffenbachia. When I checked further, there also was an accumulation of the clear liquid in several places on some leaf surfaces. The weeping continued after I tried to soak up the liquid with a paper towel last evening, but seems to have subsided at last check. Is this a phenomenon that you are familiar with and does it indicate the plant is stressed? Otherwise, the plant looks healthy and has put out a number of new leaves in recent weeks. (e-mail reference)

A: This is a perfectly normal function of the plant. It is exuding the carbohydrates from the openings on the leaf surface while the plant is fully turgid. On the surface, those openings are known as stomata. On the leaf tips, they are known as hydathodes. In essence, this is a fat and sassy, well-cared for plant. It is so well-cared for that it is drooling all over the place!


Q: I bought a dieffenbachia about six years ago. Lately it has developed about eight pods. I want to collect the seed but I am not sure how long I have to wait before the seeds are ready. (e-mail reference)

A: I cannot find any information in my references. My guess would be to allow the pods to dry naturally and then remove the seeds. Sow them no deeper than they are large, keep them warm and moist and see what happens.


Q: I have a dieffenbachia plant that I've been taking care of for six to nine months. For the past three to four months I've noticed a fungus growing on it. There are also small gray balls in the dirt which might be spores or egg sacs. The gray balls are filled with fluid. When they are squished, they pop and ooze a clear fluid. I have been spraying Schultz insecticidal soap on the plant for the past two weeks, but it doesnít seem to help. (E-mail reference)

A: I have no idea what the gray balls might be. Your photo clearly shows a mealybug infestation. I would suggest soaking a cloth in rubbing alcohol and wiping the leaves completely on both surfaces. Whatever those balls are on the soil surface, remove them to be on the safe side.


Q: After successfully rooting some cuttings from my dieffenbachia (compacta), the parent and some cuttings started to yellow all over, put out small and deformed leaves and almost halted all growth. After trying everything, I discovered spider mites everywhere. I rubbed each leaf, tapped the leaves to knock the mites off and gently hosed everything down. I will spray with insecticides tomorrow and repeat. Is the deformation permanent? Is higher humidity favorable? How do I protect the rest of my house? For the winter, the whole "family" is boxed up under a 16-hour florescent light, with the temperature set at 80 degrees and 25 percent humidity. (E-mail reference)

A: I did mention coffee in one of my responses to another insect control question. It was in reference to using strong cheap coffee after it has cooled to get rid of soft-bodied insects. The concentration of caffeine has a detrimental effect on their nervous system, proving that anything can be a poison if the dose is high enough! Your plant and offshoots sound like they will survive, but the deformation will remain on those particular leaves. To protect the rest of the house, mist the plants on a daily basis especially the undersides of the leaves. Spidermites are as effectively controlled with a spray of water as they are with insecticide/miticide applications.


Q: Can you tell me if the pods that form on the top of my dieffenbachia are harmful to the plant? Should they be cut off? Someone told me the pods are there because the plant is happy in its location. Someone else told me they should be cut off because they take all the plantís energy. I have three large pods on the top of my plant. (E-mail reference)

A: They are not harmful but some people feel the pods disfigure the plant and remove them. The pods are the end product of sexual reproduction. The plant would probably do better without them unless you want to collect seed.


Q: I have a diffenbachia that I received as a gift about a year ago. I divided and transplanted it into a larger pot shortly after receiving it. I have it in my office in a north window. Lately, I've been noticing that the new leaves are very small. Does it need more light or fertilizer? Also, I wanted to share with you that I had an amaryllis that bloomed at Christmas and then bloomed again for Valentines Day. Both times it was absolutely gorgeous! (Mandan, N.D.)

A: The diffenbachia is developing leaf size in relation to the environment it is in. I wouldn't push the fertilizer too much, but would suggest trying to locate more light for it, and as long as there is active growth taking place, keep adding small levels of fertilizer about once a month. Congratulations on your Amaryllis doing a double bloom! That is indeed unusual and enjoyable. Expect a long "recovery" now that all that energy has been expended. It may be a couple of years before you see it bloom again.


Q: My daughter recently received a Dieffenbachia. It was beautiful. Now the leaves are getting yellow and are curling. Any suggestions? (Steele, N.D.)

A: It sounds like it is getting "sunburned." If it is getting direct sun at all, move it. This is one of these "office" or "parlor" plants that do well in low light situations.


Q. I have a Dieffenbachia picta, Rudolph Roehrs. It has lost the leaves on the bottom but the top is beautiful and continues to develop leaves. It is getting kind of top heavy. Can I repot the plant in a deeper heavy container so that all the bottom without leaves would be under the soil? Would the covered stem develop roots or rot? I am also wondering when do I bring out my geraniums to repot them and do I completely cut them back and watch new leaves and stems emerge from the crown? (Fargo, N.D., e-mail)

A. Good question. I don't know what the results would be. It could root if you wounded the stem in a couple of places at about 1 inch below the soil line, and assuming that you would keep the well-drained media moist, but not wet, you could likely get roots developing at those points.

A method I have used that works 98 percent of the time is to cut the plant back to about a 6- to 9-inch stem, then take the remainder of the stem that was cut off, and cut it into about 3-inch pieces. Take those pieces and lay them horizontally in a sand/peat mix, and half cover these pieces with the media. Keep moist, and in about six weeks leaves will emerge from the ends that were nearest the bottom. Or, you can take the top that you have cut off and simply try rooting it in a pure sand medium. The cut-off stump will usually develop new leaves shortly as well.

It may be a good idea to wear rubber gloves when you are handling this plant, as it can cause a rash on some people.

Your geraniums may be just about right for repotting now. You would first want to immerse them in tepid water for a few hours to rehydrate them. Then if there are stems long enough, take cuttings and attempt to root them in sand. Otherwise, pot up the mother plants and set them in as sunny a location as possible, keeping them watered and fertilized as they start showing new growth. Set them out, of course, when all threat of frost is over.


Q: How do I take care of my dieffenbachia? (Montreal, Canada, e-mail)

A: I am growing a dieffenbachia in my office too, and in spite of my neglect, it seems to grow quite well! Your plant likely needs a little more energy in
the form of fertilizer. I don't know what to recommend to you in Canada as far as a product goes, but if you can find a non-flowering houseplant
fertilizer, that would be the one to use. It should have an analysis something similar to 10-10-10.

Also, be sure to turn the plant once a week to keep it from growing in a crooked manner. Water it a couple of times per week with tepid tap water,
fertilize it once per month, and it should just about take care of itself from there!


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