December Blossoms of Japanese Flowering Cherry (Prunus subhirtella)

Observation by Phoebe Okey-Dobie and her mother:

Some Japanese flowing cherry trees (Prunus subhirtella and possibly Prunus serrulata) were observed in blossom on Vancouver Street near Beacon Hill Park on November 29th, 2016. On that date, there were many blossoms on four or so cherry trees on that street. I returned with Tom Okey and my brother on December 3rd, and observed that one tree in particular, in front of 311 Vancouver Street, still had many blossoms on many of its branches (see Figures 1-2). This tree also had a pair of hummingbirds sitting on and flying around this tree (Figure 3), as well as a flock of small gray birds. These hummingbirds were found on and around this blooming tree, but not around other cherry trees on the street that were not blooming. The other small birds were also found mostly on this blooming tree, but not on others.

Dr. Tom Okey writes:

A warmer than usual climate during 2014-2016 might explain these December blossoms of Japanese flowering cherry (P. subhirtella or P. serrulata) in Victoria, BC, Canada. The Northeast Pacific coastal ocean region was anomalously warm in 2016 and for the last three years (see Figures 4-6).

Dr. Yasuyuki Aono of Osaka Prefecture University in Japan has assembled a 1200-year time series (recorded since 800 AD) of the dates of peak-bloom of Cherry Blossoms in Kyoto, Japan (Figure 7). This amazing data set shows that the date of cherry-blossom peak-bloom in Kyoto has rapidly shifted from mid-April to the beginning of April since the mid-19th Century (Aono and Kazui 2008; Aono 2015).

Shifts in the seasonal timing, or phenology of plant and animal species are tracked through the National Phenological Network, through their Nature's Notebook program. A data sheet and sampling protocols are provided for tracking phenological changes in Prunus serrulata at this species' Nature's Notebook page. A LEO Project could also be started employing these protocol and potentially others.

Dr. Richard Hebda writes:

I track the monthly global temperature regularly. And absolutely 2016 will be a record warm year. Interestingly the sudden onset of cold conditions will put the early bloomers and growers back in their places. Hopefully most had not yet broken dormancy. We may see some damage on the less hardy species. Concerning the flowering cherry, Thomas Munson, who works for Victoria City Parks, verify that two cherries grow at the address noted above: P. serrulata and P. subhirtella. The image appears to show P. subhirtella which is known to sometimes flower in December and has the common name of winter-flowering cherry. It is noted to flower from autumn to spring in some places. Some other Prunus species flower all winter long in Victoria, but not usually the one in the photograph.

References

Aono, Y., 2015. Cherry blossom phenological data since the seventeenth century for Edo (Tokyo), Japan, and their application to estimation of March temperatures. International Journal of Biometeorology 59, 427-434. http://dx.doi.org/10.1007/s00484-014-0854-0.

Aono, Y., Kazui, K., 2008. Phenological data series of cherry tree flowering in Kyoto, Japan, and its application to reconstruction of springtime temperatures since the 9th century. International Journal of Climatology 28, 905-914. http://dx.doi.org/10.1002/joc.1594.

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