Cherry Blossoms

This graph of the bloom time of the cherry trees in Japan has been making the rounds on Twitter:

Its creator says she made it for her mom, based on this data. 

I first heard about how long the Japanese have been tracking the bloom time at a garden club meeting, when it was used as a trivia question. I don't remember the wording exactly, but it was something like, Which plant has had the arrival of its blooms recorded for the longest time, for more than 1,200 years?

Aside from the obvious downward curve — toward earlier blooms — at the right end of the graph, the things that stood out to me on the image were:

• The sheer amount of difference, from annual weather, between the latest and earliest bloom, varying from at least a week into May to at least a week into March — even without counting the three earliest ones at the far right end of the graph.
• The way that difference has decreased in recent years, as the bloom time overall has gotten earlier. It looks like the variation is down to three- or four-week swing, rather than as much as six.
• The Little Ice Age is visible in the high point in the curve in the upward trend line around 1750.

The cherry blossoms have been blooming in Washington D.C. for these past several days of March, and my relatives near there told me on Thursday evening, March 23, it was in the 70s in northern Virginia and 80 in Richmond that day.