Be consistent with watering lawn

The consistent rain and generally cooler temperatures this summer have kept lawns green and growing through June and into July. Established bluegrass lawns need the equivalent of 1 inch of rain a week, either from rainfall or watering, to actively grow and stay green.

To determine how long it takes your sprinkler to deliver 1 inch of water, set out a coffee, tuna or other shallow can with straight sides and time how long it takes to fill an inch deep.

Water the lawn deeply once a week rather than lightly several times a week. Deep, infrequent watering promotes a deeper root system, which will make the grass hold up better to stress. If your soils are heavy clay and long periods of watering cause water to run off, you may need to split the watering into a couple of times per week.

Be consistent with your watering practices: Either water on a regular basis all summer or let your grass go dormant during hot, dry periods. I do not water my lawn, and it generally looks good unless there is an extended period of hot and dry weather in summer. Then it goes dormant and slows its growth so I have to mow less often.

Mowing your lawn at a height of 3 inches or more will help the grass withstand stress and keep out weeds.

Continue to groom your perennials and annuals by removing yellowing foliage and spent flowers. Gently pruning back more vigorous perennials can help keep your border from looking overgrown. Cut leaves off at the base to reduce the size of the plants without having them look pruned.

You may want to let certain dried flowers on plants such as astilbe and coneflower to remain standing for fall and winter interest. Goldfinches visit my coneflowers in fall and eat the seeds.

Make note of perennials that have flopped and need staking so that you can install a support system next spring before the plants need it.

The cool, wet weather this year has caused some perennials and annuals to rot. There is not much to do about these situations other than replace the plants with new ones.

Other plants may be stunted and have yellowish foliage; give these plants some time and they may recover, providing the weather gets drier and warmer.

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