Q.Black Spot Treatment Caused Heavy Leafing, No Roses
After reading advice online from this website, I used a product made by BioAdvanced called “All in One Rose and Flower Care” on all the bushes in my rose garden. I followed the directions EXACTLY. The roses proceeded to leaf out beautifully, healthy and with NO black spot which is what I was treating. However, there are NO FLOWERS on the bushes. I understand that too much nitrogen can cause this, however the label states 6-9-6, so I do not think there was too much nitrogen. I live on coast of NC and black spot is my toughest problem with my roses. I thought I had it licked, but surely don’t want a bunch of rose bushes with no roses! They still appear healthy after about 8 weeks. I called the BioAdvanced helpline and spoke to a real person who was absolutely no help at all. What is safe for me to do to get roses on these bushes??? Last year Miracle Gro for roses gave me lots of flowers, but I still had the horrible black spot all season, in spite of all my efforts. I am newly retired from work, have lots of time to spend gardening and I’m really working hard at it. Please help if you can! Thank you!!
Certified GKH Gardening Expert
I would be careful with MiracleGro products. Many of them contain slow release nitrogen, which over time will build up in the soil. Once this happens, flowering will halt until the soil has been leeched of excess nitrogen.
Sometimes, adding phosphorus and potassium can help negate some of the effects of Nitrogen toxicity, but a proper leeching will be a better fix.
You can plant Nitrogen hungry plants nearby to help with the issue, as well! They can help remove some of the extra food in the soil faster than if left to do so on its own.
https://www.gardeningknowhow.com/garden-how-to/soil-fertilizers/too-much-nitrogen-soil.htm
https://www.gardeningknowhow.com/ornamental/flowers/knockout-roses
