All of our Knockout roses appear anemic.. The bushes are thin, very little green vegetation, the branches are almost all gray,,,,,,,,,,,Never had this issues in past but did begin to appear last year. The bushes are all over 7 years old…….
They probably need a heavy pruning to rejuvenate them. I would give all of the some water that has both a product called Super Thrive and root stimulator in the same water. Water them with a fresh batch of this mix the next 4 to 5 times they need watering. I would also give them all 1/3 cup kelp meal, scratch it into the soils and water in. You can use the same water mix noted above to water in the kelp meal.