Short-term changes in early spring weather

The striking difference between the early spring weather in 2012 and 2013 is noteworthy. This year's long, cold spring is not unheard of. If anything, it was the very early spring last year that was unusual.

I have been keeping phenological data since 2002 and looked over the numbers. Because plants are great integrators of climate, I compared first blooming dates for three early-season bloomers: early buttercup (Ranunculus fascicularis), violet wood sorrel (Oxalis violacea), and golden Alexanders (Zizia aureus).

Year	Ranunculus	Oxalis	Zizia
2002	missing	4/23	5/1
2003	4/15	4/20	4/19
2004	4/8	4/16	4/8
2005	3/24	4/14	4/14
2006	4/11	4/19	4/17
2009	4/22	4/22	4/22
2010	4/2	missing	4/4
2011	missing	missing	4/21
2012	3/25	4/3	4/5
2013	after 4/14	after 4/14	after 4/14

If you look at these numbers, you can see that there has been quite a lot of variation from year to year, and that 2005 was also an early year. The early buttercup is the first plant that flowers in our area, and in 2009 it did not flower until 4/22, which is a week from now. Time will tell!