A blog post I wrote a while back “Lime and Sulfur Spray – Great Way to Knock Down Fungus On Your Roses” got a terrific response from all of you. So much so that I’d like to continue this discussion on disease prevention.
Here is my second tip for helping prevent disease on your roses.
That is not a misprint. I actually just said doing nothing can help your roses with disease prevention.
How does this work?
Roses, like all plants, have natural immune systems. And while under attack from fungus their natural immune system actually ramps up and becomes more active. And in my experience the more I expose my young roses to the local strains of fungi like blackspot, the more immune to them they become.
Think of a young child on their first day of school or kindergarten. At first they catch every strain of cold around. But after becoming exposed to them their immune system adjusts and they get fewer colds. But they have to catch, or be exposed to, that strain of cold to become more immune to it.
It’s the same with roses.
There is some thought that constantly spraying our roses with chemicals actually prevents them from building up their own immune system. They become lazy because the spray does all the work. Personally I don’t want the “Couch Potato” rose planted in my garden!
Additionally, there is thought the chemicals might actually interfere or suppress the natural immune system. Many plants fight fungus with natural fungus of their own. The chemicals don’t discriminate between harmful and beneficial fungi. Just like insect killers don’t discriminate between the aphid and the lady bug.
Stopping spraying your roses to allow them to build up their own immune system means you garden isn’t going to look so good for a while. It takes time for them to adjust. It also means newly planted roses might not look good for the first year or so as they adjust to your area. And some roses won’t adjust at all and should simply be replaced with a more disease resistant one. After all, this whole concept starts with Garden Roses that are naturally disease resistant.
But in the long run doing nothing means you will have healthier plants that are better able to ward of disease on their own. I know this for a fact because the now some 400 roses in my home garden have not been sprayed for close to 10 years and each year they get better and better.
I accidentally found this out myself. I received a beautiful pot of blooming red roses and placed them on display in my courtyard until I found that the leaves were turning a dark color. I quickly separated it from my umpteen-year-old planted roses thinking that they might catch whatever was ailing this year old plant. I never got around to throwing it out because it was a gift and because I didn't have the heart to toss it. However, I only watered it and never treated the problem. Then, gradually, it recovered and until now, I didn't know why. Thanks for enlightening me about the advantages of letting them fend for themselves.
Thanks for sharing your experience!
Paul, thank you so much for this information. I am struggling with raising roses, both HT's and Antiques in a very hot and humid climate. The only time I have had to spray is for chili thrips, other than that I NEVER spray. My antiques are huge and covered in bloom, my HT's are very different. They never achieve the size of plants which are regularly sprayed with all the chemicals and I have seriously thought of pulling them all out. After reading your advice on spraying I will persevere and hope they are just building an immune system!
Kentish, Keep in mind that in order for a rose to be successfully grown this way it must be disease resistant in the first place. Sadly many HTs from the last 30 years or so were not and will likely never be happy without chemicals. Give them a little longer but don't be afraid to get out the shovel!
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