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:
It’s not difficult to recognize blackspot, (Diplocarpon rosae). The fungus initially reveals itself as tiny black spots on foliage.
In very short order, the black spots become surrounded by yellow halos. These are not halos of the angelic sort, but the kind which inform you that your rose is in trouble.
The infected leaves will eventurally 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, controls 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.
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.
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We inherited eight rose bushes with our house. Instead of removing them I thought I would give my hand at raising them even though I have never gardened in my life. They are doing well, but then came the dreaded black spot. I was picking the infected leaves every day, but it persisted. After a long search online I came across the milk/water solution. I have to admit that it works, but you must do it weekly. I missed one week and I regretted that. The only down side to me, is that I get white spots on my roses from the milk but at least they are healthy!
Sean – Glad to hear this treatment worked for you. I made my first application yesterday evening. Although I noticed a slight trace of milk-residue on the leaves this morning, I can’t say the appearance bothers me. Better to have “white spot” than blackspot, right?
I too have blackspot on 2 of my rose bushes. I plan on trying the milk spray (as soon as I can work it into my crowded schedule). Thanks for doing the research and finding an organic solution!
So glad to have read this as my rose bushes have blackspot too! I’ve been picking off the leaves consistently. Does it matter what type of milk, whole milk or skim milk? I will be trying this remedy and hope it works!
Rebecca – That’s great!
Cheryl – I used whole milk. But according to Jeff Gillman, any kind of milk will work (except chocolate).
I will have to try this as one of my roses gets the black spots every year. Also, one of my roses, a light pink one, gets brownish outer petals before it opens. Do you know what would cause that? I think the rose is a celsiana. I am thinking maybe to much dampness and not enough sun.
I did it this morning and the white spots make them look as if I had used solfto di rame and calce but instead of that, which I hardly know how it works, the dosis and the mix, and the fear that it burns them or if too diluted doesn’t work ……. evviva finger crossed ……. and I’ll tell that everybody thanks again
Terry – You are right. Too much moisture (either from overhead watering, abundant rainfall, or high humidity) can cause the edges of rose petals to turn brown.
mada – Glad you tried the milk and water solution. As I said earlier, better “whitespot” than blackspot!
Would it work on the black spots on black eyed susans?
Joan – I know the milk-and-water solution works on blackspot and also powdery mildew, so maybe it will work on whatever fungus has attacked your black-eyed susan plants. Worth a try, anyway. Just remember you’ll have to spray weekly.
Hi Kevin: I am new to your posts. You have a very nice site. So glad to have found it. I tried the milk/water routine last night, as my roses every year have blackspot. No matter how clean or how well I disinfect the area, it returns year after year. I also sprayed the bee balm, and even the bottom leaves of the Queen of the Prairie, as both of those have shown signs of blackspot. I’m looking forward to seeing positive results. *fingers crossed* Thanks for the tip!
Oh I see you mentioned that this works on powdery mildew! I will be anxious to try this on my cucumbers and squashes, as every year they get that bad especially towards the end of summer. We have a lot of humidity where I am.
I’ve tried it, and it didn’t work for me, but I live in NC where the humidity is quite high most of the time. I have better luck with bacillus subtilis spray once a week. It is also a biological control, so it won’t really cure, but will control fungus. It’s best to spray all plants weekly whether they show signs of fungus or not.
I am going to try this on my roses and phlox. Need to get a new spray bottle first. I have been trying to avoid using chemicals now that my kids are playing in the garden and I have become more aware of the nastiness of many of those products.
Thanks for the tip! I’ll try the milk. I’ve been using fungicide and would rather stay organic if possible. Blackspot seems to have hit early this year due to the very rainy May in the Mid-Atlantic. I usually don’t have an issue this soon. It’s been an odd spring for roses here (Philadelphia) after the very mild winter.
As an aside, My Gallicas (Apothecary’s Rose and Rosa Mundi) never get blackspot, but do suffer from powdery mildew – the only roses in my garden which do. Odd. I’ll try the milk remedy on them as well.
Thanks so much for this information! Last year my 2 roses had horrible black spot & I did nothing but this year, if it rears its ugly head I’ll be prepared!
What about Neem oil? When would you use the milk solution versus Neem? I found that Neem works great for mildew issues, but love the idea of the cost savings of milk!
Fantastic advice that I can’t wait to try! I also have neem oil which I’ll try. I have other plants besides roses that are having fungal issues such as my lilacs and boxwoods. Thanks for the tip! Milk & water is less costly and easier to mix than neem, so I’m off to the kitchen now!
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Would this work on Loquats as well? My loquat leaves have black spots and have lost a lot of leaves. We thought it was blight and my husband has been spraying it with copper. Maybe
milk would be better.
Thanks for the tip! I also inherited roses when I moved to a new house and while they are all in much better condition than when we moved here, I have noticed that I have 3 plants that seem prone to developing blackspot. I have used a fungacide/miticide drench hoping to stop it this year to no avail. With all the rain it is back in force. I hate to denude the bush removing all leaves with even a hint of spot on them, so I am GRATEFULL for something else to try.
Any suggestions to destroy cucumber beetles without harming the bees? They swarmed my roses last summer & are back in force already.
Thanks for so much helpful info!
My grandmother, in the old days, used her dishpan water with the soap in it, and poured it over her roses to rid of mites and black spot.
I will do it today! Is it best to use organic milk ( hormone, etc-free) or doesn’t it matter?
I’ve never commented on this thread, why is it saying I did?
Is it half milk and half water?
Will that work on the black powdery mildew on my jade tree?
Does this work on Iris??
going to try this trick on my pear trees outside. what ever it is turns the leaves ugly and the fruit ugly as well and huge orange spores. hey, tried 2 drops of dish soap and water to a sprayer to get spittlle bugs off my plants and that sure worked with out cost too. Thanks again (spittle bugs make a foamy substance when eating plants)
first year here for black spot and it’s rampant. will use ArtistryFarm fresh goat milk and see what happens…THANKS!
I am so glad that i got this helpful hint. I am getting ready to mix some up after this post. Thank you and I will let you know the outcome on my roses.
Pam
I’m lactose intolerant and almost never haver milk on hand, so I use a Neem Oil spray. I apply it every other week, making sure to get all the leaf surfaces. It also works really well for downy and powdery mildew. An added bonus: it works well for roseslugs (the little green worms that skeletonize the leaves) too! It’s best to spray Neem early in the morning or in the evening to avoid spraying the bees.
I’ll be doing your mlk and water spray this week, thank you for a healthy way to attack
You have the wrong roses. Get medieval roses that smell great and get very little fungal disease and are winter hardy. Try: Rosa centafolia; Tuscany rose(Rosa gallica v. Tuscany); or Apothecary rose(Rosa gallica v. Apothecary).
WS
Recommend Reading Article by Mike McGrath, You Bet Your Garden Radio Show (PBS), on gardens alive web site. I use compost tea and compost on the ground to eliminate and control black spot on roses. Compost tea is magic.
http://www.gardensalive.com/article.asp?ai=458
I use whole milk (not diluted) on my zucchini, cucumber and pumpkin plants whenever powdery mildew strikes. Our climate (in Melbourne, Australia) is reasonably dry, and it works really well. A once a week application is great, but I’ll often spray twice a week to really make sure it works. It may be a slightly less effective treatment than store bought sprays….but I like the ‘no chemical’ approach.
I have spots on my peonies and impatients?
I use a 1 to 3 mixture of milk and water as a foliar feed or for watering any outdoor plants. It is an amazing fertilizer. Plants become so healthy that they resist most attacks.
This past winter I began watering with the rinse water from milk containers. I milk a cow so there are many containers. My orchids were dazzling and for the first time ever I had a fuscia come through the winter with no aphid attack or leaf loss and it bloomed constantly.
This was of ccourse raw milk so there may be an enzymatic property.
Kevin, Thanks for the milk & water spray for roses. I have an arbor with 2 climbing rose bushes that always gets black spot. Hopefully, now I can truly enjoy walking through it to get to my perenial garden. Do you have a tip regarding “slugs”?? I have over 100 hostas in my garden and this year (with all the rain) my hostas look like it’s already September rather than June. I try to stay “green” in order to keep my bees happy, happy, happy and my 4 grandchildren supplied with honey, honey, honey!!!
I’m sooo happy to have found your website with all your tips on gardening, (I’ve trimmed my boxwood and are now trying to create more from the cuttings). Your recipes (the cinnamon rolls were dee-leesh and will be trying the doughnuts this weekend).
Please keep posting!!
This would be great for commercial gardeners to know, since the world would be a much better place if poisonous fungicides and manmade pesticides were eliminated (all are derived from oil).
Perhaps large farms that routinely spray toxic fungicides could make use of this milk and water solution, as well, since pesticides are becoming much more expensive and we’re tired of having them contaminate our drinking water with poisons. Thanks for this.
I, too, was happy to see that it will work on powdery mildew as I have two roses that just insist upon hosting the fungus. I am new to organic gardening and was disappointed that the commercial pesticides didn’t seem to be affecting these particular roses. As a result of discovering your sight, I have given up on my systemic methods for the sake of the local honey bees and had admitted defeat until now.
I have another question: some of my roses turn brown before they’ve ever opened and when they finally do open, the flowers are stunted and have a sickly color to them. What am I doing wrong?
The milk and water combo also works really well on powdery mildew on lilacs too! I had a horrible summer with that in 2011, and so far, 2012 looks a bit rainy as well so I’m going to be going back to the milk and water on the lilacs again!
Will this work on lawn fungus?????
Does this work on Hydrangeas?
Sadly, I just found this advice. I have two roses that suffer from black spot every year. I diligently remove the spotted leaves, from the plant and ground. The bushes produce well, though the black spot is ever present. This year it appears my hydrangea, which neighbors the roses, has also caught the spot. I will be “milking” all three from now on. Thank you!
Hi i have a garden full of roses and love them but this blackspot is driving me crazy!! Its mostly limited to 2 rose bushes that are beside each other, though i have found it on some of the other roses also now and then. I have been using bought stuff like resolva ect and it does work but the blackspot just keeps coming back and its getting expensive. I will definantly try this milk solution and let you know how i go. Thanks for the tip
@Renae, sounds like you have harlequin beetle..they are black and orange. I just got rid of these nasty little critters thankfully. They get into the flower and turn them brown also they dont open properly. I used vinegar,dishwashing liquid and water spray. Seemed to work
tho you do need to spray them every few days.
I know honey is also supposed to be great for fungus. I’m wondering if you mixed a little honey in with the milk if that would help or hinder??? I think I’ll try that as well!!
Thanks for the advice!
Every year I end up with sticks on my rosé bushes instead of leaves. Have been looking for a cure for black spot for a long time.Even master gardeners at a local garden show were no help. Boy do I have to enlighten them at this years show. Thanks so much.
I am showing roses at my county fair this year, and I have to say that his is very odd, but my plants are in need of something to get rid of the blackspot. I’ll give it a shot!
I just hope it works within 2 weeks…?
I once heard Martha Stewart say that she uses milk, with a little soda added for her rose spray.
I’ve poured this mix in the ground near my tomatoes monthly to keep them healthy. Will the spray also work on rhododendrons with black spot?
I don’t keep very much fresh milk, could I use dry milk?
Thanks a lot for the tip, I saw this only now. My ice berg roses and Don Juan rose have this black spots. I will try this milk therapy. will this work for aphids too? My dahlia leaves are falling off.