Stems of rose are going black in vase at cemetery. I put flower feeder in the vase — is that causing the problem? It’s also shaded by
a large tree.
Once the roses have been cut from the bush, even with the preservative mix that is added to the water, they begin to die. In order to keep the roses looking fresh longer, you would need to prune off about 1/2 inch of the canes every 2 to 3 days, 4 at the most. The openings at the cut ends of the canes begin to seal over and thus none of the preservative is taken up into the canes any longer. Some cut roses start the end sealing process faster than others and will start to wilt and die back fairly quickly.