Shear Low-Growing Perennials
Catmint, veronica, salvia, and some other low-growing perennials will give rise to another flush of blooms if the flower stems are sheared just below the old flowers. The lower down on the stem you cut, the longer they will take to rebloom.
Spray for Blackspot on Roses
As soon as you spy the telltale black spot ringed in yellow on your rose leaves, it's worth trying this home remedy: Mix 2 tablespoons baking soda plus 2 tablespoons liquid soap into 4 quarts of water. Coat the leaves with the spray, and reapply after heavy rain.
Stop Pruning Trees and Shrubs
Stop pruning trees and shrubs. Any pruning done after July will stimulate new growth that might not have enough time to harden off before cold weather arrives. This can result in winter injury to the plant.
Tending Plants in Rainy Weather
The long stretch of rainy weather in many areas means soggy soil and plants. To avoid spreading disease, try to avoid walking among your plants when they are wet. It's not too late to spread hay or straw as a mulch, which can help keep disease spores from splashing up onto plants. When the soil dries, lightly hoe the surface to break up any crust that could impede water penetration, then lay down the hay or straw. Harvest frequently so fruits and vegetables don't rot on the plants.
Pick and Freeze Berries
Even if you can't eat them all right now, take advantage of the abundance of fresh fruits and berries. Freezer jams are surprisingly easy to make, or at the very least freeze some berries for later use. Simply spread them out on a cookie sheet and place it in the freezer; once they've frozen, pour them into freezer bags and seal.