May Flowering Phenology

by Carl Strang

In May, plants at Mayslake Forest Preserve continued to bloom around 2 weeks early, as compared to recent years. Here are the specifics: the median difference between 2012 and 2011 for species that first bloomed this May was 16 days earlier this year, with a range of 86 days earlier to 3 days later among 64 species. The median difference vs. 2010 was 11 days earlier in 2012, ranging 48 days earlier to 12 days later in 41 species. The median difference vs. 2009 was 18 days earlier, ranging 42 days earlier to 7 days later for 43 species.

Foxglove beard tongue was reasonably representative, blooming first on 21 May this year, 17 days earlier than last year, 5 days earlier than in 2010, and 15 days earlier than in 2009.

The difference from previous years diminishes somewhat from month to month, but I don’t expect things to even out before July or August.


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