Blackspot, and other fungal diseases, are a huge problem here. Without fungicide, my roses will lose their leaves. The rose would then have to expend its energy reserve to replace those leaves. Without leaves, the rose loses its ability to produce carbohydrates for growth and flowering. I want my roses to grow and flower, not sit there and struggle to grow leaves.
I use Bayer Advanced Disease Control fungicide. NOT the Bayer product with insecticide and fertilizer, and NOT the one you mix and pour on the soil. The concentrate in the blue bottle … for some reason, it’s only available at Lowes and some specialty nurseries. It’s good stuff, reasonably priced (around $15.00), and it’s worth the effort to find it.
Spray Day this year has been every other Thursday. It takes me about 2 ½ hours. My sprayer is a 2-gallon pump sprayer.
With 600+ garden roses here to care for, and the 400-or-so Inventory Roses, I have to fill the sprayer 5 or 6 times. With a garden this spread out, going back and forth to the faucet to refill the sprayer gets pretty tiresome. I will soon be on the hunt for a new sprayer with a larger capacity … probably an electric one on wheels that I can pull around.
What should you do if you have only a few roses to spray? How about a little half-gallon sprayer like this:
It's available in the garden department of just about any big box store, and it only costs a few dollars.
I’m a big fan of the concept of Integrated Pest Management (IPM). This is a fancy way of saying that I only treat the pests and problems that are beyond my tolerance. Aphids? I let the birds and good bugs get them. Japanese Beetles? Sometimes I knock them into a bucket of soapy water. Sometimes I see how far I can flick them. I taught my grandson to flick them ... sometimes we have contests to see who can flick one the farthest. Mostly, I just ignore them. Thrips? These have been terrible this year, and they are destroying a majority of my buds, so I may have to resort to something to salvage any flowers at all. So far, I have just ignored the thrips, too.
The most important part of pest control is to identify the pest you are trying to control, whether it’s a fungus or an insect pest. Don’t ever throw pesticides at an unknown problem hoping to eliminate it. It’s bad for the rose, it’s bad for you, and it’s bad for the environment.