Friday 17 January 2014

Re-analysing our Plant Hunt data. 

Musk Stork's-bill flowering in Lincs
Image: S. Lambert
Members of the public have started reporting 'first sightings' of plants in flower over the past few days, leading some media commentators to wonder if this is evidence that spring has come early this year. 

Tim Rich, Co-ordinator of BSBI's New Year's Plant Hunt, was a little surprised to hear this: it did not chime with the findings of BSBI botanists and members of the public who recorded what was in flower over the New Year period. So, he re-analysed the data in terms of spring- summer- and autumn-flowering species. This is his comment on what he found:


Red Dead-nettle flowering in Wilts.
Image: T. Havenith
"Whilst a very few spring flowers can be found flowering early, the dominant feature of the winter weather is the late mild autumn with lack of frosts which have allowed an amazing 221 species to be recorded flowering by members of the Botanical Society of Britain and Ireland over the New Year period.

Of the 221 species recorded only 8 (3.6%) were typical spring-flowering, native species such as Primrose or Lesser Celandine, and these represented only 2% of the 1075 total records.  

In contrast, species continuing to flower from the autumn such as knapweed or yellow-wort made a massive 91% of the species in flower (69% of the records overall).  

Ten species (4.5%) were those which typically flower all year such as Groundsel or chickweed (28% of all records), and one species, winter heliotrope, normally flowers during the winter.

Just as one swallow does not make a summer, a few snowdrops do not make an early spring".

Many thanks to Tim for doing this re-analysis. So, which are you seeing in your neck of the woods: early spring flowers or late autumn flowers? 

4 comments:

  1. Phil comments from VC66: The mild winter with no really severe frosts so far has certainly allowed a lot of late summer flowers to keep going here in Durham - my last-year's marigolds are still blooming well in the garden, as is Genista anglica (? grown from purchased seed that might not be G.anglica but is certainly Genista).

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  2. A few years ago I had a naturalised Cowslip in the garden which flowered after mowing in the Autumn and stayed in flower throughout the winter. I think this & similar phenomena of spring flowers flowering earlier may combine two effects: an second flush flowering in Autumn combined with absence of frost. It would be interesting to follow some of these flowers through the from late Autumn.

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  3. My own observations in Taunton area chime very much with those reported by Tim et al. Mostly this is about last year's summer-flowering species still being in flower. Typical spring-flowering species are no earlier than normal. Indeed, some, like lesser celandine, are even a bit later than in previous recent winters: for lesser celandine, my observations since the late 1990s suggest that first-flowering dates are as much related to wet/dry soil conditions as they are to temperatures: flowering may actually be delayed a bit in wet winters, despite mild conditions making one imagine that dates would be earlier.

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  4. Yes, the Press whips itself into a frenzy at the snowdrop of a hat! Dr M

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