The most noticeable aspect of the garden, toward the end of July, is its dryness. Not enough rain will often be the issue in mid July for the Murrysville area. Most gardeners are spending these high 80’s and 90’s days watering as much as possible. Father Gervase Degenhardt, of the Pittsburgh Rose Society, whose garden in Lawerenceville some of our ladies visited in June, recommends deep, slow watering if roses haven’t received two inches of rain per week. The water should permeate the ground to 6-8 inches. Adding summer mulches holds the moisture and helps to keep down weeds.
Insects and diseases abound, too, in the garden. In dry weather, look out especially for red spider mite, a microscopic spider that defoliates, especially roses, starting at the bottom of the plant and working its way up.
The affected leaves have a mottled look and soon fall off. The way to be sure that the mite is the cause of the infestation is to take a white paper, a sample leaf, and shake it over the paper. You can then see the tiny spiders as they fall off onto the paper. You may also find little webs on the backs of some leaves.
It is recommended by most growers to feed roses (climbing and other roses) now, but not after August 15, so as to keep new growth from being killed by frost when fall arrives. Irises and chrysanthemums can also e fed. You may dig and divide heuchera now and plant in well-prepared soil, keeping it watered until it roots. The pruning done in summer is mostly dead-heading of flowers, but forsythia and shrub roses can be shaped at this time.
Perhaps the most important chore now is the slow and thorough watering, preferably done during the morning before the sun is able to evaporate the moisture, and not toward evening, when the moisture would lie on the plants and invite fungal infection. Outside of weeding, it’s the most beneficial thing that can be done for your plants.
Some of the above hints were taken from “The Rockwell’s’ Complete Guide to Successful Gardening” by F.F. Rockwell & Esther C. Grayson.