Hortiscope

Ronald C. Smith, Horticulturist
NDSU Extension Service

Q: What pre-emergence chemical can I use in my perennial flower garden, and how often do I need to apply the chemical? (New England, N.D.)

A: I would suggest Preen as a general recommendation. Be sure to follow label directions for timing and rate.

Q: I have a spider plant that has been really beautiful until lately when the leaves have started to turn yellow. I don’t want to lose this plant, so what do I need to do to make it come back to life? I love my plants and give them plenty of TLC, so I am really nervous that there is something seriously wrong. (Carrington, N.D.)

A: Just as some kids can get spoiled from too much TLC, the same can happen to houseplants.

Try giving them a little "tough love," where you hold back somewhat on the watering, especially during the winter months. More houseplants are killed from over-watering than all other causes combined.

Q: This is not a question, but I think I can answer the question as to why glads change color.

I don’t think they ever change color, it’s just a matter of reproduction. Anyone who has dug glads in the fall will have noticed that some have at least three nice-sized corms while others will have only one. In a short time the one producing three will have many more corms. Of course there would be some that would produce more or less, but on average those that produce more continue to produce more each year. (Mahnomen, Minn.)

A: Your comment makes good sense -- after three years, who can keep all those corms straight?

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: I am fortunate in having several paces available to place a garden. My favored spot lies between two groves of trees and is almost completely protected from wind damage and drying. The same trees that protect it, however, also shade it partially. I would estimate no part of the garden gets more than six hours of sun on a summer day. Is this possibly the reason why I seem to get more upward growth (sometimes spindly) than fruit production (tomatoes, for example)?

What vegetables might be most appropriate for this area? The other favored area has complete sun but a high water table under it (near a small lake or slough). It is high enough that trees started near it have died over the years. What "crops" might be best for this area? I have had terrible luck growing vining crops (regardless of area, watering, fertilizing, etc) such as squash, pumpkins, and gourds. We have a hive of honey bees nearby and there always seems to be bumble bees around also. Any suggestions? (E-mail reference)

A: Vegetables, especially those that bear fruit like tomatoes and peppers, need as much sunshine as they can get to produce that fruit. Shade causes the plant tissue cells to elongate and cell walls to become thinner. In essence, the photosynthetic factory that produces energy for fruit production is greatly reduced, resulting in poor or low fruit production. The best crops to grow in such locations are the leafy ones like lettuce, mustard, Swiss chard, and possibly cabbage. You can still grow something in the full sunlight/high water table location. I would suggest going with a raised garden. Get some 1" x 12" boards and cut them into appropriate lengths, secure them to the ground with stakes, and bring in some good sandy loam from an outside source. Voila -- you have an instant productive garden, and should be able to grow any legal crop there. Fruit set on vine crops like cucumbers, melons, etc. is dependent on bee activity, and bee activity is dependent on the weather cooperating. Many times the flowers are open and the wind is high, it is raining, or it is too cold, and the bees cannot do their job. When that happens, locate the male flowers, remove, and use them as pollinators to the female blooms that open. The difference between male and female blossoms is quite obvious, and the best example I can think of for educational purposes is the Easter lily. When the flower opens, the two sex organs are apparent–the yellow, pollen-laden anthers and the pale-green pistil (usually with a sticky surface). With cucumbers, the flowers are either monoecious -- each plant producing female and male flowers -- or gynoecious, which produce only female flowers. In those varieties, the seed packet will have some pollinator-plant seeds coated with a colored dust for identification. Then there are also parthenocarpic cucumbers which are seedless, and have renounced pollination altogether. On monoecious plants, the first blossoms to appear are the male, followed by female blooms, which delays fruit production. The same basics hold true for the other vining crops- - melons, squash, and pumpkin. If you want to assure bee activity, interplant with borage. I did one year, and had enough fruit off the vines to start my own farmer's market! So, the bottom line: be sure you know what "type" of vine you are planting, and make sure you do everything possible to assure insect activity. They do a much better job of distributing the pollen than we do. Otherwise, seek out the first blooms, which are male, and go to work on the female flowers when they open.

Q: I was wondering if you could give me some ideas of what type of climbing plant I could plant by a large cottonwood tree. It is just a large tall stump. (E-mail reference, Morris, Minn.)

A: Honeysuckle vine grows quickly and covers well. Get the Halls cultivar -'Halliana Prolific', grows to 20' or more, with white, maturing to yellow flowers, very fragrant.

Another one to try is the Japanese wisteria - 'Wisteria floribunda', which will grow 30' or more, and is noted for wrapping itself around tree trunks quite nicely. The flowers are a violet blue color, and the fruit is a bean pod, which lasts well into the winter.

Q: I have seen several questions about Cyclamen plants. I have a plant that we have had for five years. We keep it in the shade in the summer and in the winter indoors where it gets lots of light and even temperature. It has been repotted once, and it has been in bloom most of the time. (E-mail reference, Eureka, S.D.)

A: Thanks for letting me know that it is possible to keep a Cyclamen going. Whatever you are doing, keep it up, and write a book about it.

Q: At Christmas in 1999 I received three poinsettia plants. They never do well indoors for me. The plants I had looked very bad, losing most of their leaves. So I said what the heck, and planted all three plants together outside. I never thought they would live, but the plant was beautiful this year and had wonderful color. Now with winter soon to be over, what should I do to take care of the plant? I have heard that they should be cut back, but how much should be cut and is there any other care I should worry about? (E-mail reference, Tampa, Fla.)

A: Poinsettias grown outdoors will tend to become leggy and unattractive, so the only care needed is to prune them to suit your tastes so they make attractive outdoor shrubs. Keep the soil on the slightly acid side with peat moss and fertilizing with ammonium sulfate. Toward the end of summer, thin the branches so that larger red-colored bracts may be produced around Christmas. Also, you can take cuttings while the shrubs are still vegetative and root them in peat moss quite easily, for your own houseplants next holiday season. Cuttings should be about 9-12 inches long.

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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.

Source: Ron Smith, (701) 231-8161, ronsmith@ndsuext.nodak.edu
Editor: Gary Moran, (701) 231-7865, gmoran@ndsuext.nodak.edu