Remove weeds from your lawn before they set seed. You can use a trowel or asparagus knife to remove weeds like dandelion, plantain, and clover if there are only a few of them. If you don’t have time to pull the weeds, spot treat weedy areas with a selective herbicide for broadleaf weeds. Do not spray on a windy day and be sure to use a sprayer that produces a coarse spray rather than a fine mist to avoid drift that is harmful to other plants in your landscape. You can also prepare a small amount of herbicide and use a disposable sponge and disposable rubber glove to wipe the herbicide on the weed foliage.
Check wild cherry trees and apples for Eastern tent caterpillars. During the day, the fuzzy black caterpillars rest in silken webs in the crotches between branches. Remove the nests, caterpillars and all. A stick or pole may be helpful for removing nests that are out of reach.
If you’re doing some spring mulching, be sure to do the job right. Use no more than two inches of mulch and keep it a few inches away from the trunks of trees to prevent decay of the bark. Avoid covering the crowns of perennials or shrubs with mulch, since it encourages diseases such as Southern blight.
Instead of purchasing beneficial insects, conserve those that nature sends your way. Spray pesticides only when it is absolutely necessary, and treat only the plants that are being attacked by pests or diseases. Whenever possible, use a reduced-risk pesticide such as horticultural oil, insecticidal soap, or neem seed extract to combat pests and diseases. These pesticides have minimal impact on beneficial insects. Look for insect predators when you note a burgeoning insect problem; they may be working to bring it under control for you. You can avoid using pesticides that harm beneficial insects by exploring other control options. Physically remove pest insects from their host plants with a jet of water from your garden hose, or hand pick them into a bucket of soapy water. Be sure that you are providing your landscape plants with the conditions they need to thrive; healthy plants are less likely to be subject to pest and disease problems. When shopping for new plants, be sure to select pest and disease resistant varieties whenever you can.
Resist the temptation to rush spring growth with heavy applications of fertilizer. Lawns, if fertilized now, will be much more prone to disease when hot, humid weather arrives. Heavily fertilized trees and shrubs are better hosts for aphids, scale insects, and diseases such as fire blight. Make a mental note to fertilize in the autumn when most plants are making new root growth and are best able to use the nutrients you apply. Spring flowering bulbs are an important exception to this rule. Fertilize them as the flowers fade to promote healthy foliage that will result in a bigger bulb and more flowers next spring.
Check azaleas, andromeda, and rhododendrons for lace bug hatchlings. Look at last year’s foliage; if you notice yellow stipples on the leaves, it is likely that last year’s lace bugs laid eggs on the underside of the leaves. The black eggs are well camouflaged by the tarry black excrement left by the adult lace bugs. It is easiest to detect them using the beat test. Place a white sheet of paper under the foliage and tap the plant vigorously. Young lace bugs are black, spiny, and no larger than a pinhead. If you detect large numbers of them, spray infested plants with horticultural oil, insecticidal soap, or a pesticide containing acephate.
Ovulinia petal blight may cause azalea flowers to turn tan and mushy if rainy weather coincides with their bloom. Apply a fungicide labelled for petal blight to your azaleas when the flower buds have begun to show color. The life of the flowers may be prolonged by as much as two weeks with this treatment.