Brown spots on rose leaves are among the most common problems encountered by gardeners. Rose bushes are among the more difficult flowering bushes to grow, primarily because they are vulnerable to a wide range of plant diseases. Those who wish to garden organically don't have the wide arsenal of chemical sprays to turn to that solve all your rose problems in one spray but may have deleterious effects on the environment. Fortunately, organic methods of getting rid of brown spots on rose leaves are available.
Things You'll Need
How to Get Rid of Brown Spots on Rose Leaves
Step 1: Use Careful Watering Practices
Prevent brown spots before they become a problem by practicing careful watering. Brown spots on roses are nearly always the result of a fungus; hence, good moisture control is essential to keeping them at bay. Don't water the leaves of a rose bush, only the root area. Avoid allowing plants to become crowded, and don't plant roses in a high-humidity area of your garden, such as an area that receives less sun or where mold problems have occurred before.
Step 2: Prune Rose Bushes
Prune rose bushes well to promote healthy growth and to allow air circulation around your rose bushes. Clean your pruning shears and any other garden implements that touch roses well, to prevent spreading mold from one plant to another.
Step 3: Check for Too Much Sun
Inspect plants to verify that the problem is, in fact, fungal. True brown spots always are; however, brown curled edges of leaves are a sign of scorching. Observe whether the spots are evenly distributed on the leaf or whether the browning is at the edges. If it's primarily at the edges, and the leaves are curled as well as discolored, excessive sun exposure is the culprit.
Step 4: Move the Rose
Move the plant to a shadier area after the last flowering if the cause is too much sunlight.
Step 5: Check for Pest Infestation
Look for signs that the brown spots are caused by pests instead of a fungal disease. If the spots are yellowish, rather than brown, insects may be the cause. Look for bugs on the leaves to confirm.
Step 6: Apply Insecticidal Soap
Apply insecticidal soap if the symptoms indicate a pest problem instead of a fungal issue. Premixed insecticidal soap is easy to spray directly on the roses without diluting. Ensure that you spray in all affected areas. Since the insecticidal soap only works on the bugs that are actually on the plant when you apply it, you might need to reapply the insecticidal soap each week or every other week to contain the insect problem.
Step 7: Apply Organic Fungicide
Spray rose leaves with organic fungicide if a fungal problem has been established. Follow the package instructions exactly to treat the rose bushes..
Step 8: Mix a Baking Soda Treatment
Use a baking soda mix as an alternative to commercial fungicide if you prefer. Mix 1 part baking soda with 15 parts water and place in a clean laundry spray bottle. Spray it on the rose bush.
Step 9: Reapply Fungal Treatments
Reapply fungal spray once a week and after any rainfall. If the infestation is small, remove diseased leaves and discard them in the garbage. Don't discard them outdoors, since this can lead to the fungus spreading.
Christina Inge is a freelance writer, marketer and designer with more than 12 years experience in the consumer and business-to-business fields. She has a bachelor's degree in English and a master's degree in adult education and instructional technology. Her interests include technology, marketing, textiles and health.