How to Treat Diseased Roses Without Chemicals

Plant roses in full sun. Give them plenty of room to spread out without touching each other, other plants or a fence or wall because air circulation is critical to preventing disease.

Amend the soil at planting time with rich compost, manure and organic fertilizer. Top with compost each year in spring and fall. Mulch around the rose with bark chips to keep moisture levels even and discourage weeds.

Water roses weekly by soaking them at the base, not with a sprinkler or hose that will wet their foliage. Fungal diseases such as rust, mildew and black spot grow briskly on wet foliage and are spread by water and wind.

Fertilize roses monthly with an organic fertilizer formulated for roses. Organic fertilizers release their nutrients slowly, as the plants need them, so they don't encourage fast, weak growth more susceptible to pests and diseases, the way that some chemical fertilizers do.

Spray your roses with an organic fungicide containing copper or sulfur as soon as the first leaves emerge in spring. Continue to spray every 10 days or as directed on the package.

Pick off infected leaves and prune off infected canes, wiping your pruner with bleach after each cut. Clean up any fallen leaves from the ground. Dispose of infected foliage in the garbage; don't compost it. Spray the rose, even if it is now denuded, with organic fungicide every 10 days as new leaves appear.