Question
I took cuttings off a Red Knockout rosebush and rooted it. Last year the bush bloomed red. This year it is blooming pink. Why?

Answer
Could be several reasons
The fertilizer you use can make a difference.
Is the rose that you made the cutting from still blooming red?
If it is, and you are using same fert then the ros?is reverting to its original parents color
If it is planted in a dif area, then add coffee grounds to the soil, ph is prob high.

It can also be that you took a cutting from the root stock, instead of from the main plant. Always take cutting from highest part of the ros?
Follow the stem and make sure it comes from the main plant and not from the root stock.

Hope this helps you.