Plants tell us in their way they're ailing

Q: I have an anglewing begonia that lives in my greenhouse. Its leaves began curling up in tight curls from the sides toward the middle and then turning brown. What do I need to do to treat this problem?...

Q: I have an anglewing begonia that lives in my greenhouse. Its leaves began curling up in tight curls from the sides toward the middle and then turning brown. What do I need to do to treat this problem?

A: I don't know. It could be from herbicide drift (you didn't say where you live), mealy bug or mite infestations, or any number of fungal diseases.

To save time, I suggest you contact your local Extension Service office to find out if there is a horticulturist or plant diagnostician who could assist you in getting the problem identified. Go to www.csrees . and click on your state and then county for your local office.

Q: Is the cyclamen toxic to small animals such as cats?

A: Cyclamen contain toxic saponins, although the number of serious exposures is very low. The plant was investigated for toxic and pharmacologic properties in the 1950s and '60s. However, there has not been much research since then that I can find. Apparently, the highly toxic part of the plant is the rhizomatous tuber, which the cat is unlikely to get into. However, I would do my best to keep the kitty away from the plant if possible.


Q: My croton lost all of its leaves. When we got a cold spell, I covered the plant, but I guess it couldn't take it and all the leaves turned brown and fell off. How do I know if it is still alive?

A: I'm relatively sure it is still alive. The stems should be green under the bark. If not, the crown should have life left in it. I'm willing to bet that with the arrival of warm, spring weather, it will begin to releaf for you. At the very least, it should send up some new growth from the crown.

Q: Is it possible for an African violet to display stress because of workers suffering from colds or flu in an office setting? I have had two plants on my desk for quite some time, but have not had problems until now.

Prior to my office, they did very well in my home. Yesterday, both looked just fine. When I came in this morning, I noticed that the larger one had developed three droopy lower stems. Nothing has been changed in their routine during the past eight months.

The leaves and stems look fine, just droopy. They haven't bloomed since last fall and don't appear to show any signs of developing budded stems. Prior to this, they bloomed just fine. I water from the bottom once a week when needed. I use filtered water that is diluted with Peters African Violet Food.

A: How nice it would be to get a sympathetic acknowledgment from our houseplants when we are not feeling well! Unfortunately, this is not true. What has likely happened is that up to this point, the plants were silently suffering some kind of cumulative stressors, such as temperature, light, water, drafts, insects or disease, but didn't show any symptoms until now.

It is somewhat like going somewhere where you get into unsanitary conditions, but the symptoms don't show up until a few days later, so you can't make sense of what it is that ails you. As a sweeping statement (I've said this many times before), the majority of houseplant problems are from two sources: overwatering and/or underlighting. I think the problem may be too little light intensity. In an office setting, the fluorescent lighting degrades through time. The problem is little noticed by the human eye, but is picked up by the energy preceptors in the plant's chlorophyll mitochondria as it fades in intensity.

This is why changing the fluorescent lights on a yearly basis is recommended for optimal plant health and vigor. Our vision will notice the duller light intensity about a year or two later, so get the bulbs changed to make it easier on our eyes.


Unless the plants in the office are tolerant to low-light conditions, such as the sansiveria or Chinese evergreen, they will react much sooner than the human eye can make the detection. The fact they haven't bloomed since last fall gives me a hint the problem may be the lighting.

To contact Ron Smith for answers to your questions, write to Ron Smith, NDSU Department of Plant Sciences, Dept. 7670, Box 6050, Fargo, ND 58108-6050 or e-mail .

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