Q. I found some strange-looking plants in a wooded area near my home. The tops look exactly like elderberries with the purple fruit, but the trunk is covered with large thorns. I've never seen an elderberry with thorns. What do you think it is?
A. Aralia spinosa, known as Hercules club or devil's-walking- stick. It is not related to elderberry, although the fruiting heads are similar in appearance. The berries are toxic to humans.
Q. I grow lots of different salad greens in a large cold frame during the fall and winter. This has been a source of great lTC enjoyment to my family. Unfortunately, a "concerned" neighbor is scaring my wife with horror stories of nitrite poisoning. She claims that the greens accumulate nitrates at high levels in the winter. Is this true? If so, can anything be done about it?
A. Nitrate and nitrite are both a type of salt. Nitrates do accumulate in salad and leafy greens at high levels during low-light conditions. Spinach, turnip and collard greens accumulate twice as much nitrate as lettuce. The nitrates in a plant may have been converted to nitrites before you ingest the plant or the process may take place after ingestion. Nitrites reduce the blood's ability to carry oxygen, and they may form carcinogenic compounds in the body.
In this area, however, we have a relatively high percentage of sunny days during the fall and winter, which helps to minimize the problem. And if you follow these precautions you can grow fall and winter greens with relatively low nitrate levels:
1) Harvest greens on sunny days in the afternoon (nitrate levels are highest in the morning and on cloudy days).
2) Don't fertilize with blood meal.
3) Harvest greens before they are fully mature.
4) Eat the greens immediately after harvesting or store them for short periods at 32-34 degrees.
Q. I have an old orange tree that I move outdoors each summer and bring indoors in October. This year it seems to have mealybug on it - small, white, cottony things. What's the best way to treat it? I really prefer not to use chemical insecticides.
A. Mealybugs are a common pest of citrus plants that move in and out of doors. Kill them by dabbing each mealybug with a cotton-swabbed stick that has been dipped in rubbing alcohol. You can also spray your tree outdoors on a mild day with an ultra-fine horticultural oil or a houseplant insecticide containing pyre-thrum. Good luck; this is a tough pest to control.
This Week's Checklist
1. Take care not to break tree and shrub branches when hanging Christmas lights outdoors. Don't drive screws or nails into healthy wood, and don't use wires that are frayed or that have cuts in the plastic insulation.
2. When bringing evergreen boughs indoors, keep them away from drafts and heat sources. (They will dry quickly and drop needles if exposed to too much heat.) Spray the boughs beforehand with an anti-desiccant to make them last longer.
Pub Date: 12/20/98