Change in Rose Flower Color

Our rose bush had burnt orange blossoms for 7 years. This year, we have dark red roses growing on the same bush. It also seems that it hasn't grown as tall.

This is a common problem with grafted roses. Most hybrid teas, some grandifloras and climbers, and a few floribundas are grafted. Propagators graft a single bud of the desirable rose, burnt orange in this case, onto a hardy root system. If the grafted portion dies the hardy rootstock takes over. Cold winter temperatures are usually the culprit. I have also seen cases where shoots from the rootstock sprout and flower along with the grafted portion. Remove the rootstock-shoots to prevent them from outgrowing the more desirable rose. In your case you can either enjoy your "new" rose or replace it with one you prefer.