November 20, 2003

Hortiscope

Ronald C. Smith, Horticulturist
NDSU Extension Service

Q: I brought my fuchsia and geraniums inside because there was a forecast for frost. Subsequently, some very tiny insects that looked like baby flies started flying around the house. Could these be plant related? (E-mail reference)

A: Very likely. They will usually disappear when the central heating is cranked. The dry air dehydrates them.

Q: The roots of our cottonwood tree are taking over the lawn and approaching our concrete patio. Should we attempt to take the tree out? (E-mail reference)

A: You should contact an International Society of Arboriculture certified arborist. A certified arborist is bonded and insured and can do the job in a professional way by cutting down the tree and then grinding the stump and most of the major roots.

Q: Would you have a list of possible causes of apple trees failing to bear fruit? I see the timeline normally listed is two to five years. Is there something about scarifying an apple tree's trunk to stimulate fruit production? (Hettinger, N.D.)

A: There are several reasons an apple tree will not bear fruit. Some varieties take as long as seven years to bear fruit. Pollination may not be possible if the apple tree is located in a windy area. The buds will die as they begin to harden if the tree is located in a frost pocket area. Wet, cold weather during and after pollination can cause a tree not to bear fruit. Too much TLC, turf fertilizer and water, may delay the tree’s entry into the reproductive stage of growth. Also make sure the variety you are using is hardy enough for your zone. "Traumatic stimulation" has been used to get trees into bearing modes for centuries. In some cases it is clubbing the tree with a stick or bat; girdling stems. The best method that seems to work and cause the least amount of damage to the tree is to take a sharp shooter spade and drive it into the ground around the canopy spread of the tree in about a half dozen spaces. This action cuts back on the root volume somewhat and sometimes traumatizes the tree into reproductive activity.

Q: We have an almost 100-year-old Christmas cactus that my husband’s grandmother gave me about 12 years ago. Since getting it, it has gotten bigger and much more dense. She kept it in part of the house that had no heat but it still flowered a great deal. I’m surprised it never froze and she even rooted cuttings in ice water and they bloomed too! Because it stays outdoors here every summer, it grows more in an upward fashion rather than hanging like some do. It's in an 11-inch clay pot and, when watered, it weighs 22 pounds. (E-mail reference)

A: What you’ve told me just proves that plants can get along very well under less than what we think are ideal conditions. So often we think our prescriptions for plant care will do the trick, when all we need do is let nature take it's course. Thanks for sharing!

Q: I'm once again trying my hand at growing aloe and jade. I've not had much luck growing them. Everyone tells me I overwater. How often should they be watered and when is the best time to transplant? (E-mail reference)

A: Jade and aloe are succulent plants, which means they posses fleshy leaves and stems with the ability to store water so if you think they need to be watered, they don't. In fact, most succulents can go a month or two without water during the winter dormancy period without harming the plant. When spring arrives, water can be applied more liberally, allowing the media or soil to dry completely between thorough waterings. Be sure the plants get plenty of bright light, indirect and direct, for part of the day. Repot only when the top part of the plant is too big to be supported by the container. I think too many people repot these plants too often resulting in setting them back and possibly causing damage. If repotting is necessary, do it coming into the spring when there is active growth.

Q: The leaves on my jade tree are not plump and juicy. Many are somewhat shriveled but not falling off. I can't help thinking that this is an indication that I need to water it more frequently. I've been maintaining a once-a-month watering schedule. It did seem to me the last time I watered it that the leaves plumped up. (E-mail reference)

A: Once-a-month watering is about right, without knowing anything else about the plant's setting in the environment, which I assume is close to normal. The winter months are typically a dormant or non growth time for succulents, with some flowering, like the Christmas cactus, during that time period. Water when the foliage appears to be shrinking or losing its plumpness.

Q: My poinsettia was doing so beautifully outdoors this summer I couldn't bear to cut it back so I brought it inside before a hard freeze. It is now losing leaves. It is in a south window. What should I do? (Sioux Falls, S.D.)

A: It will eventually re leaf so don’t worry. Be patient and keep it evenly moist but not soggy and in a south window.

Q: I was given two crown of thorn plants in 2001. They haven't bloomed since. I re potted them this summer and got plenty of leaf growth but no blooms. Can you suggest how I can get these plants to bloom? (E-mail reference)

A: Patience, along with good direct sunlight and warm temperatures, should work. Don't overwater or over fertilize and certainly don't mist. It will flower when it is good and ready.

Q: About a month ago I purchased two houseplants from a local retailer. They are thriving except some leaf edges have been turning brown. While repotting, I noticed little, almost translucent colored worms in the soil. I should have done the smart thing and tossed both plants but I really like them. I removed as much soil as I could, almost down to bare root, and transplanted them. Can I add an insecticide to the soil? Also, what were those little bugs? (Glyndon, Minn.)

A: They could be the larval stage of springtails or some other insect that feed on organic matter. I would advise against adding any insecticide to the soil. Try to water with low salt water as much as possible and do not over fertilize. Generally the burning or browning on leaf edges is the result of too much salt or poor drainage. The container should be free draining, and excess water that pours through the container bottom should be dumped within a 1/2 hour after watering. As long as you repotted with sterile or pasteurized soil, there shouldn't be a problem.

Q: I have a wandering Jew plant and two Tahitian bridal veils. Are there any special directions for growing them? Occasionally the bridal veils develop an odor almost like cat urine. Could the odor be in the soil that the nursery used? (Glyndon, Minn.)

A: It has to be the soil from the nursery. They probably have cats they use for biological control of certain pests and the cats think the potting soil is for their use. Get pasteurized or sterile soil that is in a bag and hasn't been used by any cats! Both plants will benefit from strong, indirect light and even soil moisture maintenance. Both are tough and easy to grow, surviving on benign neglect. They also benefit from being moving outdoors during summer months.

Q: Are you familiar with mutations such as having partially pink petals and white petals with a pink line in the middle of the petal in otherwise all white miniature or wild type cyclamens? (E-mail reference)

A: Those are usually somatic mutations known a chimeras. Many apple mutations are the result of this process.

Q: Why does a cactus not have leaves? (E-mail reference)

A: Most cacti are lacking in traditional leaves because of the environment they evolved in. Their adaptation is one of survival by storing water as long as possible when it is available through an extensive root system that is very efficient at absorbing water from the soil when it rains. In a typical leaf there is a large amount of water loss through the stomatal openings that are found throughout all leaf surfaces. The cacti have adapted by being leafless and growing spines but not thorns. Thorns are stem modifications and spines are leaf modifications. Spines on cacti do not carry on photosynthesis, but the stems do. Note their green color. Spines provide a microclimate for the cacti by shading the rounded or ribbed stem from the blazing sun of the desert where they dwell. Spines also play a somewhat protective role for certain animal species in the desert, giving shelter to some from predators, while others can consume cactus parts that are covered with spines with no ill effects. They certainly are a deterrent to we humans who might absent mindedly stroke, steal, or smell the flowers that occasionally bloom on them. Interestingly, the cacti species that are in full exposure to desert sun have a denser covering of spines than those same species that may be growing in canyons or the shade of large boulders.

Do you have a gardening or houseplant question? Write to Hortiscope, Box 5051, NDSU Extension Service, Fargo, ND 58105 or e-mail to Ron Smith at ronsmith@ndsuext.nodak.edu. Note to e-mail correspondents: please identify your location (city and state) for most accurate recommendations.

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Source: Ron Smith, (701) 231-8161, ronsmith@ndsuext.nodak.edu
Editor: Rich Mattern, (701) 231-6136, richard.mattern@ndsu.nodak.edu