Add a ring of mulch around tree trunks

Trees planted in lawns can benefit from a mulched ring to reduce competition with grass roots and keep mowers and weed whips from damaging trunks. If the tree is small, mulch out to the drip line of your tree. If this is not feasible, extend the mulch as far as you can. Even a 6-inch-wide mulched saucer will help protect tree trunks from serious damage.

Do not mound mulch or soil around trunks because it is unattractive and can cause rotting at the base of the tree.

Prune out water sprouts (vigorous shoots on the inside of the tree and on the trunk) and suckers (vigorous shoots growing from the base of the plant). Crabapples and hawthorns tend to send out lots of water sprouts and can benefit from this type of pruning.

• Cut back bulb foliage when the leaves have turned yellow with little to no green left. This indicates the bulb has gone dormant, and the foliage is no longer producing food to store in the bulb for next year's growth and flowers.

• Mow your lawn at a height of 3 to 3½ inches to help the grass handle the hotter and drier weather typical in a Chicago-area summer. A healthy, thick lawn will help choke out weeds.

• It is important to identify insects on your plants before treating them with an insecticide to determine whether the insect really is a problem. If it is, assess whether the damage being done warrants control.

The presence of insects feeding on the plants should not necessarily trigger a treatment. Some insects are beneficial and help control other insects naturally.

If an identified pest is causing significant damage, it is important to use the correct control with proper timing. If a variety of treatments are available, use the least toxic control possible.

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