Get rid of suckers. Many trees and shrubs, especially grafted ones like roses and some fruit trees, send up weak shoots from the base of the trunk or roots. Remove them off before they begin to compete with or even overtake the plant. Using sharp pruning shears, cut them off as close as possible to the trunk or root.
Prune hedges. Shrubs grows faster at the top. To counteract top-heavy growth, clip a hedge slightly wider at the base, slanting it in at the top. Use electric or hand-operated hedge shears for fine- to medium-leafed shrubs. Use pruning shears on large-leafed shrubs, cutting off growth branch by branch. Trim at least three times a year, when new growth is about 6 inches long.
Protect saplings. Nothing knocks down weeds around saplings as well as a string trimmer, but nothing is more likely to girdle the tree and eventually kill it. To protect the trunk of a young tree, cut a short length of flexible black plastic pipe (wide enough to fit around the tree), and split one side. Open up the pipe, then slip it around the trunk. As the trunk expands, so will the sleeve. With time, the tree will fill out and start casting enough shade to reduce the weeds around it. Then you can remove the sleeve.
Trim annual flowers. Cut off dead flowers to encourage blooming. If heat causes annuals to stop producing flowers, cut the plants back by half and continue to water and fertilize; most kinds will perk up and start blooming again when the weather cools.
Harvest flowers for drying. Cut everlasting flowers for fall arrangements. Baby's breath, globe amaranth, immortelles, statice, and strawflowers should be harvested just before they open fully. Strip off the leaves, bind the bunches with rubber bands, and hang them upside down in a basement, garage, or other cool, dark place.
Water wisely. Most plants die from overwatering, not underwatering, so irrigate only when needed (check soil moisture first). To reduce evaporation, water when temperatures are cooler and air is still, usually in the early morning. Water deeply to moisten the root zone, but no deeper. Adjust irrigation systems so sprayers or sprinkler heads don't direct water onto pavement. Soaker hoses are an efficient way to deliver water along rows of vegetables or flowers.
Build your soil: Composting is a great way to recycle yard and kitchen waste. In return, you get a valuable soil conditioner. Do compost: coffee grounds and tea bags, fruit and plant trimmings, and washed and crushed eggshells. Don't compost: bones, dairy products, fish, grains, grease, meat, pet feces, weeds with seedpods, diseased plants, or sawdust from plywood or treated wood. Keep the pile moist and turn periodically.
Pop in some late-summer color: Many perennials reach their bloom peak in spring and summer, but there are plenty of flowers that will carry a border into later summer and fall. Choices include aster, cape fuchsia, chrysanthemum, coreopsis, daylily, gaillardia, gaura, Japanese anemone, lavatera, Nemesia fruiticans, rudbeckia, Russian sage, salvia, and summer phlox. Before shopping, check to see which plants are best adapted to your climate.