First sign of grubs may be critters digging in the yard

Grubs can be a problem in lawns some years. The adult beetles will be attracted to irrigated lawns that are surrounded by dry lawns for their egg laying in early summer. If the season is dry, and you are the only one watering the lawn on the block, you will have a greater chance of having grubs.

Your lawn may or may not have a problem with grubs this year so deciding not to apply grub control will not necessarily result in a grub infestation. I do not water my lawn at home, nor do I ever apply grub control and have not ever had any problems with grub damage.

Typically, when there are 8 to 12 grubs per square foot, visible damage will occur as they feed on the roots of the grass. The lawn will brown later in season when hot and dry weather increases stress on the lawn. Raccoons and skunks will dig in lawns to find and eat the grubs — this is often the first sign of grubs.

Be sure to read the label carefully to make sure you are using the right product at the right time of year. Products designed to prevent grubs are generally applied late June to mid-July. There are products designed for quick kill of grubs. Those are applied later in season when grubs reach a threshold in the lawn, causing damage.

There is no need to control a small number of grubs, which a healthy lawn can withstand. In any case, use an insecticide labeled for grubs at the proper time of year.

• Installation of plant material can continue through the summer. Try to keep plants moist before planting to minimize stress on the new plant material.

Containerized plants can sometimes be difficult to remoisten if they are planted dry. Be sure they have been watered before planting. Plants that are grown in containers have a lighter growing medium that will generally dry more quickly than your garden soil and thus will need more frequent watering until their roots go out into the surrounding soil.

Newly installed balled-and-burlapped plants need about 1 inch of water a week. The amount and frequency of watering will vary, depending on the soil conditions in your garden and weather conditions. Sandy, very well-drained soils will dry out more quickly than heavier clay loam soils.

• 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).

Crabapple and hawthorn trees tend to send out lots of water sprouts and can benefit from this type of pruning.

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