DRAT. While inspecting my roses the other day, I discovered that some of the shrubs (like ‘Mary Rose,’ above) are showing signs of “blackspot.” Details about this insipid fungal disease, and why — according to extensive research — a weekly spray of milk and water is the smartest way to control it:
The infected leaves will eventually turn a sickening shade of yellow and then drop to the ground. And, if left untreated, the fungus will continue to attack other leaves on the shrub (young leaves are the most vulnerable). These, of course, will turn yellow and fall to the ground, too, until the shrub looks shockingly nude.
Now, I’m not opposed to scantily-clad statues in my garden. But I like my roses fully clothed.
Treatment: According to author and horticultural professor Jeff Gillman, who has conducted extensive research on blackspot remedies, a spray composed of one part milk and two parts water is the best answer to the disease. He says this simple solution, if applied weekly, will control blackspot as well as any synthetic fungicide, including Chlorotalonil.
Why does milk work against blackspot? Well, nobody knows for sure. Gillman thinks it is the lactoferrin that milk contains. Lactoferrin helps to fight diseases in people.
Of course, Mr. Gillman is talking about cow’s milk here, any fat content you prefer. I happen to prefer whole milk, so that is what I’m using.
I’m committed to spraying my roses every Monday with the milk-and-water solution. And I’m spraying not only the roses which show signs of trouble, but the healthy ones, too. Blackspot rarely limits itself to just one shrub.
Spraying is work, but it isn’t hard work. It took me less than 30 minutes to treat my 40 roses. Be sure to spray both the top and bottom of leaves. Pick up any fallen leaves, too. Otherwise, the spores of the fungus can splash back onto the rose during a rain storm, or while you water the shrub with a hose.
And speaking of watering — never, ever, use an overhead sprinkler on roses. Wet foliage — especially when combined with humid weather — contributes greatly to the spread of blackspot.
Are your roses the victim of blackspot, too? If so, please let me know if you are willing to give the milk-and-water solution a try. By all accounts I’ve read, the stuff really works.
UPDATE: After spraying my roses religiously last summer, I can tell you the method does, indeed, work. And that’s good news!
Don’t miss anything at A Garden for the House…sign up for Kevin’s weekly newsletter.