Save money next spring by taking plant cuttings this fall

It is time to take cuttings of annuals, such as geraniums and begonias, that are to be kept over the winter. Cool nights in September will harden off the plants, which will make them more difficult to root.

Take a tip cutting 2 to 3 inches long, and stick it in a well-drained potting medium, such as one part peat moss and one part perlite. Keep the cuttings in humidity and bright light. Cover the cuttings with a plastic bag and ventilate daily by opening and resealing the bag.

Once they are well rooted, typically in two to four weeks, transplant to a 2- to 4-inch pot filled with a growing medium. The size of the new pot will depend on the vigor of the rooted cuttings.

Coleus is very easy and fast to root so can be done later in the season to propagate plants that you want to keep inside over winter. I have had good luck holding Coleus over winter on a downstairs windowsill with a south exposure.

• Populations of yellow jackets (a yellow-bodied social wasp) build up in summer. They are unwelcome visitors to picnics and are particularly attracted to sweet things like soda. Practicing good sanitation is the best way to minimize any pest problems.

These wasps tend to make their nests in the ground or in stone walls, so watch these areas as you are working in the garden. When the weather is warm and sunny, there will be a lot of activity, with the yellow jackets flying in and out of the nest.

Baldfaced hornets construct large paper nests in trees and large shrubs at head height and above, so you should be aware as you are working in the garden. Paper wasps will build nests under eaves, signs, benches and fence railings and will sting if disturbed.

These are all beneficial insects so control them only if they pose a safety hazard.

• Espaliered plants can soften large, blank spaces on walls or fences when there is minimal bed space. To train espaliers, young supple twigs and branches are bent to meet design requirements. Carefully tie the branches in place with raffia or plastic tape. The ties should be secured loosely so the flow of water and nutrients through the tree's stems is not constricted.

Adjust ties during the growing season as necessary. Formal espaliers do need regular attention to keep them looking good and will likely need to be pruned several times over the course of the summer.

• Tim Johnson is director of horticulture at Chicago Botanic Garden, chicagobotanic.org.