Continue to tend to and enjoy your landscapes

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 grown in containers have a lighter growing medium that will generally dry more quickly than your garden soil, so they will need more frequent watering until their roots grow out into the surrounding soil.

Newly installed balled-and-burlapped trees and shrubs 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.

• Weeds growing between cracks in brickwork or sidewalks are unsightly but easy to eliminate. Treat them with a nonselective herbicide when they are small to avoid having to pull them out by hand.

• If your hybrid roses have been losing their lower leaves and the remaining leaves have yellowish foliage with dark spots, it is likely they have blackspot, which is a common fungal disease. Begin a spray program with approved fungicides immediately.

Fungicides need to be applied once every seven to ten days as they work to prevent the disease and do not cure what is already infected. Be sure to clean up any leaves that have fallen from the plants. Many landscape shrub roses are resistant to black spots so do not need to be on a spray program.

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