I've been reading a lot of advise about the black spots on rose bushes. I've got 12 rose bushes and about 5 of them have it bad! 2 of them almost do not have any leaves on them. I've been picking off the spotted ones, and now spraying them with whole milk,(like a lot of suggestions said) it help's but we get rain every few days or so I can't seem to keep up! they are starting to get some new growth, but wondering a few things about the milk and spraying them. looking for any suggestions... some have said use whole milk, some have said use 50/50 milk and water, how much would it matter? (I would think whole would coat them better.) I'm assuming you shouldn't use the milk cold out of the frig but how much difference? how much milk to spray on? I've been spaying so that they are pretty saturated, is that too much? Any suggestions I'd greatly appreciate it. :-? moderator's note: split this post into it's own topic
The milk spray (any kind of milk--whole, 2%, powdered) is a 10% milk, 90% water solution. It needs to be sprayed weekly, or after a rain. It is completely non-toxic to beneficial insects, and at the ratio above doesn't even show on the bush, except to make the leaves a trifle more shiny.
I read that milk is also a terrific fertilizer. I was reading about raw milk, but I'm not sure how important it is to be raw. Does the milk spray work on problems other than black spots?
The milk spray is a fungicide, so it will work on mildews (powdery and downy), smuts, and any fungal disease. Whole milk and powdered milk contain calcium, so using those also benefit the plant. A very mild fertilizer that helps the plant keep up its calcium intake. I'm so tempted to make a joke about plants having good strong teeth!
What I've noticed when I spay the milk on an open rose is that it seems to preserve it for like a week or so...I was really surprised! Marlingardener you mentioned that it works as a fungicide...would it work on the mulch mold? this yr. I have a lot of it all over my mulch! someone mentioned using soapy water on the mulch mold...but I have it really close to the rose bush. I would think the soap would hurt the rose bush! whats your thought on that??
Well, never having encountered moldy mulch I am only guessing, but I'd try the milk solution. Soapy water (1 tsp. of soap, not detergent, in 1 pint of water) is a mild insecticide and will take care of aphids, mealy bugs, etc. It wouldn't hurt your roses, but if there is a bee working the roses, it will kill the bee. I don't know about a soap solution taking care of mold.
Mulch molds, although unsightly, aren't bad.They are actually beneficial to your plants, helping to release nutrients from the mulch, making it available to the plants. I guess the only bad thing about mulch molds is that it often looks like "dog vomit". http://mdc.mo.gov/discover-nature/field ... slime-mold and http://www.gardenstew.com/viewtopic.php ... highlight=
I was told that the black spot fungus actually resides in the soil. So should i try soaking the soil once with the milk solution?
The spores aren't in the soil, but on fallen rose leaves that are infected with black spot. Cleaning up thoroughly around your roses will do more good than spraying the soil. Be sure to burn or put the leaves in the garbage--not in the compost--because composting the diseased leaves will just spread the fungus.
I wrote a little piece a few years ago about spotty leaves in roses. It doesn't add a lot to what folks here have written, but every little bit of opinion can be helpful to you. http://www.gardenstew.com/viewtopic.php?p=135582#135582 I have to say that I have tried a milk solution as part of the regimen for this type of infection; however. my experience was that it did not adequately help. The infection was too widespread...and it rained the spray off too often. Personally I believe that this disease is so pernicious and resistant to the frequent milky measures that you must take, that other types of agents are required and the clean-up and removal of infected leaves and branches to numerous and time-consuming that it will make fighting this infection a real challenge. An understatement. It requires a heavy hand and endless persistence along with a meticulous nature to treat with any sort of hope for success. Good luck there.
