Blackspot On Roses - Knowledgebase Question

Oxnard, CA
Question by Qwnbthnn
May 30, 2001
Is there an organic recipe for getting rid of blackspot ,and/or rust from my rose plants? I remember hearing about a mixture of oil soap, baking soda etc...but don't remember the recipe. Or am I confused, would this treatment be for aphids. Any help would be appreciated.

Answer from NGA
May 30, 2001


A fungus causes black spot on roses. Some cultural
practices may be helpful in controlling it. These include
planting varieties resistant to it, ensuring your plants are in a location with good air circulation, avoiding wetting the leaves when watering, and cleaning up, removing and destroying any infected leaves. Do this especially well each fall to minimize reinfection from year to year. A clean layer of organic mulch (such as shredded bark or half finished compost or chopped leaves) applied before the plants leaf out again in spring should also help prevent reinfection.

Neem oil may also be helpful. At the current time, the only
neem product I have seen that contains neem oil (rather than
the ingredient azadirachtin) as the active ingredient is Green Light's Rose Defense. It is available through Gardener's Supply Co, Burlington, VT. 800-863-1700, Neem controls aphids and mites on your roses, and the oil version of neem also will control powdery mildew and black spot.

Some gardeners have had success using baking soda and
water sprays to control black spot. Tests in England
indicated that 1.5 tablespoons of baking soda in 1 quart of
water was effective. Add a few drops of dish detergent to
help it stick. You may want to try it and see for yourself.
Caution: Always test something new like this on a few leaves and wait a few days to see the results before spraying all of your plants.

You must be signed in before you can post questions or answers. Click here to join!

« Return to the Garden Knowledgebase Homepage

Member Login:



[ Join now ]

Today's site banner is by ge1836 and is called "Penstemon Dark Towers blooms"