Q: We have a problem with bean beetles. You printed a recipe for a spray that’s not harmful to the environment a long time ago. Could you please reprint it? – G. Rominger, Brazil, Ind.
A: Some gardeners mix 1 tablespoon of liquid dishwashing detergent per 1 gallon of water and spray it on insects. Insecticidal soaps have been found to be effective against aphids, whiteflies and mealy bugs. The soap works by breaking down the outer layer of the insect, causing it to desiccate and die. This is most effective on soft-bodied insects. Hard-shelled insects, including beetles, are tougher to dry out! Still, some gardeners have success with soap on beetles.
The safest route is to use prepared insecticidal soaps sold commercially at garden centers and home stores. These products have been tested for the strength of dilution and safety for plants and gardeners. While it is true that some soaps will kill insects, some will also harm the plants they are meant to protect.
Q: My chrysanthemums grow 30 inches tall, then fall over. How can I keep them short, like they were the year we bought them? – Andrea McCann, W. Lafayette, Ind.
A: In order to create short, compact mums, growers spray the plants with growth inhibitors and cut them back regularly. You can accomplish the same thing just by removing the growing points once or twice during early growth. Pinch them back when the plants are about 6 inches tall (about mid-June) to induce branching. When the branches are 6-8 inches long (about mid-July), remove their tips to induce more branching. The procedure may seem drastic, but the result will be bushy, well-shaped plants that flower abundantly.
Many old garden sayings have a grain of truth to them. The axiom “Pinch mums until the fourth of July” may help you remember how to care for your mums.