Answer: I'm sure you are disappointed to lose your roses - especially when you thought they would be safe from root damage. The truth is, plants in containers have a whole new set of circumstances with which to deal. First, potting soil can dry out quickly so containerized roses will need to be checked often to make sure the potting soil does not get too dry (or remain too wet). And, roots in containers that are sitting directly in the sun can bake when the sunshine falls on the pot during hot afternoons. I suspect that is what happened to your roses. You can either group pots together so they can provide some shade to each other, or set the containers in the shade of a decorative stone or small shrub, or use a double layer of containers by planting in one and then sinking that pot into a slightly larger pot. You can stuff insulating material between the pots to help keep the root systems from overheating.
Hope this information is helpful~!
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