Gardening season in full gear; go ahead and plant

The gardening season is now in full gear. An exceptionally warm March this year got the season off to an early start. Some plants were then damaged by April frosts, but they should be starting to grow out of it now. With the danger of frost past, you can plant with abandon. Try new annuals to see what works and add some excitement to your garden.

General garden care

Reduce the need for pesticides in your garden by practicing integrated pest management. If you garden thoughtfully, you can reduce pest problems to a minimum. Begin by choosing the right plant for your site. Plant it properly, amending the soil with compost and planting at the right depth. When possible, select plants that are resistant to common diseases and give them the appropriate care to minimize problems.

Watch all plants carefully for insects and diseases. If trouble arises, identify the problem and decide whether you can tolerate a certain amount of damage. When damage is not tolerable, use the least toxic control measure. Timing is also important: Apply controls when pests and disease are most susceptible.

Never spray just because you see insects, as many of them are beneficial or harmless. When you use an insecticide, you kill the good insects along with the bad ones.

Groom your borders to improve the plants' appearance and maximize flower production. Gently remove dried or yellowed bulb foliage; when the foliage yellows the bulbs have already stored nutrients for next year's flowers and are going dormant. Deadhead — snip off spent flowers — on your annuals and perennials to encourage them to continue flowering. Remove yellow foliage to keep the plants neat and tidy.

My definition of a weed is any plant that is out of place. A good time to weed is when the soil is moist; the roots come out more easily. It's very important to get weeds out before they go to seed. A small hand weeder or trowel is helpful.

Pinch fall-blooming plants such as chrysanthemums and hardy asters to control their size and increase their flower production later. Pinching will encourage side branching, producing bushier, stockier plants. Make the first pinch when the plants reach 6 to 8 inches in height; most likely your plants have grown more because of the early spring, so adjust your pinching height accordingly. Remove approximately 1 inch from the tip of each shoot. When the side branches that sprout are 6 inches long, pinch them as well. These plants should not be pinched later than July 4 in the Chicago area, as flower buds are formed then and late pinching can delay or prevent flowering.

Deadhead hybrid roses as soon as the flowers fade. Many shrub roses are self-cleaning and don't require deadheading. When in doubt, lightly prune old blossoms to keep the plant looking attractive. Do not deadhead any roses that are being grown for their hip production.

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. If necessary, you also can carefully spot-treat weeds with an herbicide.

Bring tropical and other tender houseplants plants out for the summer when night temperatures remain above 50 degrees. 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 and shrubs

Trees planted in lawns can benefit from a ring of mulch to reduce competition with grass roots and to keep mowers and weed whips from damaging trunks. If the tree is small, mulch out to the drip line (as far as the branches reach). If this is not feasible, extend the mulch as far as you can. Even a 6-inch-wide mulch ring will help protect tree trunks from serious damage. Spread the mulch in an even layer 3 to 4 inches deep. Do not mound mulch or soil against the trunk; is unattractive and can cause rot at the base of the tree.

June is a good month to shear your hedges. Prune formal hedges slightly wider at their base than at the top. This ensures that the sides of the hedge will receive equal sun exposure and helps to keep the foliage full from top to bottom. Many hedges in the home landscape are not pruned properly and they are often wider at the top than the base. Pruning hedges in June will help create a more dense hedge. There likely will be more growth, so plan on shearing again in July.

Look for tree seedlings such as buckthorn, mulberry and box elder that tend to establish themselves in hedges and in the base of shrubs. If you look closely and they are easy to spot. In areas where it is not practical to dig out the roots of these weed trees, treat the stump with glyphosate promptly after cutting to kill the root system.

Planting

You can continue to install plant material through the summer. To minimize stress, try to keep the plants moist until you can plant them. Be sure that they have been watered before planting. Containerized plants can sometimes be difficult to remoisten if they are planted dry.

Plants that have been 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 than the nearby plants until their roots go out into the surrounding soil.

Newly installed trees or shrubs that were balled and burlapped need about one 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.

Think of your containers as large, exuberant floral displays when choosing plants. Mix plants of different heights for a layered effect. Include plants that will cascade over the edge. You also can group several containers of different sizes for a good effect. A simple design of only one variety of annual planted in each container can also be beautiful.

Lawns

If you had trouble with grubs in your lawn last year it is time to treat for them. Grubs feed on the roots of the grass; visible damage usually occurs when there are 8 to 12 grubs per square foot. Because its roots have been damaged, the grass will turn brown later in the season in hot and dry weather. Raccoons and skunks also damage lawns when they dig for grubs. Use a granular insecticide labeled for grubs and water it in after applying. Apply your control before the middle of July.

When using power equipment such as a string trimmer in the garden, wear protective glasses, ear plugs and long pants. The plastic line of a string trimmer can kick up debris that could injure your eyes or sting your legs if you are wearing shorts. The line also can injure the bark of trees. Power equipment can be loud, making ear protection especially important if you are using equipment for an extended period of time. I use ear muffs when mowing the lawn and whenever I use a leaf blower.

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