Prune Hybrid Roses
Prune lightly just as new growth starts after summer heat abates. Light trimming encourages a second bloom period before winter. Remove dead or weak canes, but take off no more than one-third of the plant. Feed with a slow-release fertilizer that will last through fall or use a product for flowering shrubs that contains nitrogen and phosphorus.
Start Planting Cool-Season Vegetables
As temperatures drop, start growing cool-season vegetables. Sow seeds for beets, bok choy, broccoli, Brussels sprouts, cabbage, Chinese cabbage, carrots, cauliflower, chard, collard greens, endive, kale, kohlrabi, leaf lettuce, leeks, mustard, green onions, radishes, spinach and turnips. Sow peas after mid-month. Depending on temperatures at your elevation, you may choose to wait until mid-October to avoid late heat spells that dry out soil and stress young seedlings.
Spider mites thrive in dusty conditions, and this summer continues to feature ferocious dust storms that coat plants with a layer of grime. Spray it off with a forceful blast of water from the hose. The best time to do this is early in the day before the sun heats up to prevent potential burn.
After summer winds and storms, refresh mulch as needed. Layer several inches around plants, taking care that it does not touch the trunk or stem. Wet mulch built up against the bark creates a welcoming environment for pests and diseases. Mulch moderates soil temperatures, maintains moisture, and inhibits weed germination.
Hold the Shears at High Desert Elevations
Do not cut back perennials, ornamental grasses, or summer-blooming shrubs until next spring. Butterflies lay eggs on stems and aggressive pruning will decrease next year's population. Also, stems left on the plant through winter provide energy reserves.