This is the month for pest control, boosting blooms

Most gardeners will experience problems with insects and diseases at some point. Identify the pest or disease and research the best control to use before applying a pesticide. Problems can often be prevented or minimized by careful plant selection and proper care or culture.

General garden care

Practice integrated pest management in your garden to reduce the need to use pesticides. Begin by choosing the proper plant for your site and using good planting practices by amending the soil with compost and planting at the proper depth. When possible, select plants that are resistant to common diseases and give them the appropriate care to minimize problems. Monitor all plants carefully for insects and diseases. If trouble arises, identify the problem and use the least toxic control measure when damage crosses an unacceptable threshold. Timing is also important - apply controls when pests and disease are most susceptible. Never spray just because you see insects, as some of them might be beneficial or harmless. If you use a pesticide, you kill the good insects along with the bad ones.

Pinch fall-blooming plants such as chrysanthemums and hardy asters to control their size and increase production of flowers. Pinching will induce side branching, producing bushier, stockier plants. Make the first pinch when the plants reach 6 to 8 inches in height by removing approximately 1 inch from the tip of each shoot. When the resulting lateral branches reach 6 inches, pinch them as well. These plants should not be pinched later than July 4 in the Chicago area, as flower buds are formed at this time and late pinching can delay or prevent flowering.

Mowing is one way to control weeds in a large, natural prairie area that is being established in your garden. Native plants typically develop their roots, not their foliage or flowers, in their early years, which gives weeds the opportunity to gain a foothold. Mow weedy areas now at a high height to cut back the weeds and keep them from choking out the native plants. In small areas, weed by hand.

Groom your borders to improve plant appearance and maximize flower production. Gently remove dried or yellowed bulb foliage since the bulbs are going dormant and have already stored food for next year's flowers. Prune off spent flowers (deadhead) on your annuals and perennials to encourage them to continue flowering. Remove yellow foliage to keep the plants neat and tidy.

Bring tropical and other tender plants out for the summer. You can help them acclimate to the outdoors by placing them in a shady, protected site for a week or so. Moving the plants from the inside directly to a full-sun location can burn the leaves. Bring these plants back inside when night temperatures drop below 40 degrees in the fall.

Trees

Be careful not to damage trees during summer home repairs and improvements. Typical construction activities such as excavating, changing grades, and moving materials around the yard can have a significant negative impact on your trees. A tree's roots can reach well beyond the drip line (where the rain would typically drip off the leaves), depending on the type and age of the tree as well as soil conditions. The roots will spread less in heavy clay soils. This damage to the root system can manifest itself gradually over a number of years with a slow decline in the tree's health. Twelve inches of wood chips spread along the construction route can help minimize damage to roots.

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.

Planting

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 that 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 thus 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. Sandy, very well-drained soils will dry out more quickly.

When planting a container, mix different heights of plants for a layered effect. Try something different from the typical tall plant in the center with a ring of shorter plants. Include plants that will cascade over the edge. Tilt plants slightly over the edge when planting for a more natural effect. Think of your containers as large, exuberant floral displays when choosing plants. A simple design of only one variety of annual or shrub planted in each container can also be beautiful.

When renovating the plantings around the foundation of your home, grade the soil so that it slopes away from the house. It should be sloped to move water away from the house, never toward the foundation. Over time, it is typical for soil to settle around the foundation. When adding soil around the house, make sure it is not higher than the concrete foundation. Brick can absorb water from the soil and wood siding can easily rot. Also check your downspouts to ensure that water is being directed away from the foundation. Simple adjustments to the soil grade and redirecting downspouts can prevent or reduce water coming into the basement.

Lawns

If you had trouble with grubs in your lawn last year it is time to treat for them. 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 out later in season when hot and dry weather increases stress on the lawn. Raccoons and skunks will dig in lawns for the grubs. Use a granular insecticide labeled for grubs and water it in after applying. Apply your control before the middle of July.

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