Plant cool-season greens for wonderful salads

Cool-season lettuces, mesclun mixes and other greens that were planted in early spring can be planted again this month. If weather is unusually hot, plant these greens in partial shade or wait a few days until there is a cooler forecast.

The best quality and best-tasting salad greens come from plants that are watered frequently and lightly rather than infrequently but deeply. This advice is the exact opposite to what is recommended for watering trees, shrubs, perennials, grass and other plants.

• Holes in the lawn dug by raccoons and skunks may indicate the presence of grubs, which feed on grass roots. Check for areas of the lawn that are browning or where the grass lifts like a piece of sod. If there are more than 12 grubs per square foot and you are seeing extensive damage, then you may consider using a product designed for the quick kill of the grubs.

Be sure to read the bag carefully to ensure you are buying the right chemical for grub control at this time of year. It is important to follow the instructions for application.

• If the new growth at the tips of your pine's branches has turned brown, a disease called Diplodia tip blight may be the problem. It is too late to spray fungicides now because infection occurs in the spring.

Prune out dead tips in dry weather to reduce the spread of infection. Remove all infected needles from the base of the tree and discard off-site.

• Some crabapples are very susceptible to apple scab and those not treated in spring may have lost many of their leaves. Their remaining leaves can be affected with black and yellow spots. Spraying at this point will not help combat this disease, but you can give the trees extra care by supplemental watering as needed for the remainder of this year and fertilizing in fall or next spring.

Remove all infected leaves and do not add them to your compost pile. Also, consider replacing disease-prone trees with a cultivar that is resistant.

• Look for woody plant weeds like mulberries, buckthorn and boxelders that grow up among shrubs and in hedges. These weeds tend to be hard to spot when they are young.

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