Questions on: Kalanchoe

Ron Smith, Horticulturist, NDSU Extension Service


Q: I received a kalanchoe and a spathphyllum plant for my mother-in-law's funeral. Can you plant these outdoors or do they have to be an indoor plant? Can they be set outside for the summer in a pot? Thanks. (e-mail reference)

A: At best, they can be set outside for the summer in a pot, but bring them inside well ahead of the first frost.


Q: I had a large kalanchoe plant. It was covered with small red flowers, but became so large that I divided it into three plants. All three plants look very healthy, but aren’t blooming. What can I do to get them to bloom? (Tappen, N.D.)

A: Try a very large dose of patience. They usually flower in the spring when the days get longer. Keep it in a south-facing window this winter and come April, you may be pleasantly surprised. Once the flowers start, move the plant to an east- or west-facing window or simply put the plants under artificial plant lights for 13 hours a day.


Q: I am having trouble locating a particular houseplant that my mother kept when I was young. We called it “the pregnant plant” because it reproduced by making a “baby plant” grow on the end of the leaf. The baby plant would drop into the soil (roots and all). I asked the folks back in Nebraska where I grew up if they remembered the plant. They remembered, but couldn’t come up with the actual name of the plant. Could you tell me the name of the plant? (Cresbard, S.D.)

A: No problem. I’ve been fascinated by this plant since the first time I saw it! It is called Kalanchoe spp., K. pinnata, K. daigre-montiana or K. tubiflora. Get one and enjoy!


Q: When is my kalanchoe supposed to bloom? It bloomed all summer in my greenhouse, but I would like to see it bloom for Easter. I read that the plant should be covered for about a month. I did that, but it budded within a week. How long should I leave it covered? (Onaka, S.D.)

A: These are short-day plants, which means they should be getting 12 1/2 hours of total darkness a day. All I can tell you is to go ahead and cover it. When you see buds forming, no further cover is necessary. Plant vigor, temperature and the growth stage the plant is in also are factors, but the main triggering mechanism is the lack of light exposure.


Q: I have a kolanchoe plant that I set out this spring that has refused to bloom. I would appreciate information about preserving it this winter and getting it to bloom. (Pembina, N.D.)

A: It could very well be that you have a succulent type that produces no flowers such as the kalanchoe tomentosa. The flowering types are naturally long-day (short night) plants and will commonly flower in the spring or under 14 hour days.


Q: I received a Kalanchoe plant about a year and a half ago. It was healthy and growing. For the past six months, it has been losing lower leaves. The remaining leaves have white, tiny spots, which seem to turn to fine pepper-like black spots. I have included a sample of the white spots and the black droppings. I have also included a leaf ready to drop off. It was outside for the summer and I have sprayed it with an insecticide and water several times. It is now growing new leaves at the base of the stalks which have lost former leaves. Is this plant worth saving or should I throw it out? (Glyndon, Minn.)

A: I would probably never recommend throwing out a Kalanchoe as long as there was one healthy leaf. The defoliation could have come about as a result of one or a combination of causes: overwatering, not enough light, cold drafts, or widely varying watering practices. It looks as if the leaves you sent were infected with black spot , a fungus that can also contribute to leaf drop. Your picking them off is a good practice. Be stingy with the watering between now and April, and keep the plant in bright but indirect light. Do not fertilize in winter, but begin again in April and repeat in two months. I think your plant will continue to recover for you if you follow these suggestions.


Q: What is meant when we say that a florist "forces" a plant to bloom? In my case, I am referring to the kalanchoe plant. I see kalanchoes for sale in stores that are quite small, but they are blooming beautifully. My kalanchoes only bloom when they are quite large and usually in January or February. (Casselton, N.D.)

A: Good question! Generally, when florists force plants to bloom, they push or alter one of the normal growth factors that would cause them to flower. In some cases, this is feeding with a phosphorus - and potassium-rich fertilizer. In other cases, it involves raising the growing temperature. And in yet other cases, such as with the kalanchoe, it is a day-length factor. When the days become short enough (or the nights long enough), flower buds are initiated and blooming takes place in mid-winter, as is the case with your plant.

What the florist does to force kalanchoes into flower is to provide them with artificially short days by covering them with a lightproof cloth after eight hours of daylight until flower buds are initiated. The same practice is followed with poinsettias and Christmas cactus plants.


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