When Is the Best Time to Spray Roses?

Purpose

• Home gardeners spray rose bushes to control pests and disease. Spray roses that have had past disease and pest issues in the spring before they bloom, as a preventative measure. Manual control methods -- removing leaf debris to prevent fungal problems, handpicking Japanese beetles and spraying plants with a strong stream of water to dislodge aphids -- are effective preventives on other rosebushes. When prevention fails, spray roses with a chemical application only when the infestation is so significant that damage is widespread and the bush's health is severely compromised.

Sprays

• Always select an insecticide made for roses to ensure the chemical is designed to eliminate common rose pests. The best time to treat most roses with an insecticide is after an infestation is detected, not as a preventative. Conversely, fungicides are frequently sprayed on roses weekly or biweekly as preventatives, or to treat a diseased rose bush. Two types of fungicides are available: systemic and contact. Systemic fungicides penetrate foliage and stems, but contact fungicides remain on leaf and stem surfaces. If you choose to spray roses regularly with a fungicide, alternate between the two types. This prevents roses from developing a tolerance for any one product.

Dangers

• Be aware that an insecticide application can harm good insects as well as bad ones. Furthermore, chemicals are often toxic for humans and pets that might come in direct contact with the spray. Always wear protective eye gear and gloves when spraying roses and wash your hands thoroughly with soap and water once done.

Other Prevention Measures

• Always choose disease-resistant roses for your home garden. Planting disease-resistant roses lessens the chance of infestation and limits the need to spray roses. Plant them in a sunny location. Space bushes far enough apart so that air is able to freely circulate in between them and their branches. Keep leaves and buds dry to prevent fungal spread.