Yes, own-root roses and grafted roses grow a bit differently in their first year.
Grafted roses may appear larger at first because the top growth is from a mature variety that’s been attached to a hardy rootstock. However, much of their energy in the first season goes into adjusting to the graft and establishing on their “host” root system.
Own-root roses, on the other hand, focus their energy on building a strong root system from the start. They often produce thinner, more flexible canes in the first year, and may look smaller above ground—but don't let that fool you! This root-first approach sets them up for long-term vigor and health.
After their first pruning and growing season, the difference in size and growth habit becomes much less noticeable. Over time, own-root roses often outlast grafted ones and are less prone to issues like suckering or graft failure.