Wild Rose October Bloom

Observation by Brooke Sanderson:

On a walk we spotted a few rose hip plants blooming in October. This was unusual because we typically see them blooming in June and most of them have been without blooms for months.

LEO Editor Comment:

Thank you Brooke sharing your observation. We have actually had a number of posts provided in LEO Network about late blooming wild roses, the latest was in the Fairbanks area in October 16, 2017. This is the first recorded however, since 2020. We are sharing this post with Dr. Katie Spellman, and ecologist with the University of Alaska Fairbanks. Katie hosts a project that records late bloomers (late blooming plants) report from across Alaska. We are also sharing a consult that was received about late blooming rose plants, shared by Katie in 2017. This from Pameal Diggle of the University of Connecticut. We hope this is helpful in explaining why the rose flowers are waking up for winter. See also the attached link for Weather Underground calendar view for Galena in September of 2022. Some warm days might be one explanation behind these late bloomers. M. Brubaker

"Plants rely on a variety of signals so that they go dormant at the right time. Going dormant at the right time is critical for flowers or leaves. If they delay too long, they risk being killed by low temperatures. The type of rose you saw typically begins to form its flowers in the summer, but those flowers go dormant and then expand into fully formed flowers the following spring. The flowers that you are seeing in the fall are not getting the appropriate signals to dormant. One of the goals of "late bloomers" is to understand what those signals are. Temperature is probably very important and temperatures probably do cause the plant to make some chemical signals, but those signals are not necessarily released by the plant into the environment. Rather, they remain inside the plant and cause the flowers to open prematurely."