Q I hear much about companion planting these days, but I am not sure exactly what it means. Does it imply that certain plants do well growing side by side? Does it mean some plants repel insects that might bother neighboring ones? J.V., Texarkana, Texas The answer to both questions is ``yes.'' For example, researchers have found that marigolds repel certain types of nematodes that harm plant roots.
We think we have discovered a dependable repellent for cabbage worms (loopers). We planted a half barrel full of ornamental kale, with variegated leaved nasturtiums (variety, Alaska) hanging over the sides. Not only is it a striking combination, but to our amazement, this container planting has had no cabbage worms.
Other plantings of ornamental kale, and other members of the cabbage family, have needed regular spraying with BT (Bacillus thuringiensis) to keep the cabbage looper away. Eggs are laid by sulfur butterflies. We have seen none of these around the kale combined with the nasturtiums.
Q I have had an American bittersweet vine for 12 years, and it has had nary a berry. My friend, who lives only a short distance away, has a six-year-old vine on an apple tree, which is loaded. E.P.T., Massillon, Ohio
On American bittersweet (Celastrus scandens) the sexes are separate, as with all Celastrus. Apparently, you have one that produces male flowers, while your friend's vine has female flowers. Her bittersweet is benefiting from your male vine, which is producing the pollen. If you get a vine with female flower parts, or take some cuttings of her vine and stick them into loose soil near your vine, they will probably root. Keep in mind that Celastrus fruit and leaves are considered poisonous.
Also, your friend's apple tree will soon become strangled by her vine. Bittersweet are very aggressive and shouldn't be allowed to grow on a live tree if you value it.
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