What’s wrong with my roses?
I'm a first time gardener and I'm afraid my roses may have rose canker. The first picture where the roses are very green was from about a week ago, two days after I first planted it. It was doing amazing, then suddenly its branches were turning brown. I bought it from the Home Depot, were it had been heavily pruned and waxed. There was a storm over the last week were I had to pour water out of its pot, so my boyfriend thinks it may be because of overwatering. We also dug it up today and exposed the roots more because (as we suspected) they were still pretty packed from when we bought them. When we first planted them, I gave them half a tablespoon of blood meal for nutrition. I'm planning on pruning the black stems later today when I can get some disinfectant. Is it possible to bring my plant back or is it too far gone? What do I do?
This is a sad situation but it maybe not hopeless. Your roses are diseased; it may be canker, it may be botrytis blight from being too wet. The canes may have been infected when you purchased them. Remove all affected canes to the base of the plant even if you remove every one. Clean your pruners between cuts. Take the rose from the container. Drill drainage holes in your pots or get new ones. I like to put outdoor pots on rocks or "pot feet" to assist drainage and to allow oxygen to reach the roots. Examine the roots and remove those that are soft. Soak the rest in a bucket of 10% bleach or buy a fungicide for this purpose. Use new soil to repot them, pressing the soil around the roots as you fill up the container. Add some long-acting fertilizer. Water well. Unless they are already dead, the roses will send up new shoots. Use a fungicide on the new growth, one that is rated for rose canker as a preventive measure. I can not guarantee that this will produce a disease-free rose as the canker can get into the base and roots. It will be simpler and perhaps less expensive to buy a new rose from a reputable garden center for a fresh start.