My double knockout rose is looking very sad. At the beginning of spring it was loaded with roses. Now instead of seeing new red growth and blooms on my rose, the leaves are thinning out and some of them are turning a pale yellow color. Last year it bloomed non-stop all the way through September. This year it doesn't seem to be making any new blooms at all after the first time it bloomed. Can you help me solve this problem?
Double Knockout Rose
It seems every season is a bit different due to climatic conditions. This season in my area we have had alot of rain and cloudy days. Thus we are also seeing much more of the yellowing of the leaves here on some of the roses and other plants. The roses and plants get too much water and the soils become heavy. The oxygen flow through the soils is very much slowed down and sometimes even nearly stopped. If we water the roses as we usually do, we simply add to the problem. I suggest taking a look at the soils moisture by using a moisture meter. Probe around each rosbush in three or four locations to see what the soils moisture level is. If it shows Wet, then the oxygen impedance could be part of the problem. If it is dry, then the soils pH could be the problem. Both the overly wet soils and a pH problem can cause the yellowing and thinning problems due to the nutrients that the roses could normally take up are now locked up within the soils makeup. Check the pH level of your soils too and see if it needs correction. Giving each of the rosebushes 1/2 cup of Epsom Salts worked into the soils around them will help bring back the green in some cases as well as encourage the new growth and new canes/basal breaks.
Here are some article links for you as well: https://www.gardeningknowhow.com/garden-how-to/soil-fertilizers/soil-ph-plants.htm