Apply the bark mulch only very thinly around the roses
Thank you for the hint. We have not laid any bark mulch around the roses within a radius of 5cm. It is not so easy to see in the pictures. Or should the distance be made even larger?
We have replaced bark mulch around the plants with hay. Oxygen passes through, moisture remains underneath. Disadvantage: hay is somewhat more volatile than bark mulch and therefore somewhat more labor-intensive-