Saturday, October 1, 2011

The First and Last Rose of Summer

Burnet rose Rosa pimpinellifolia is the most fragrant of all the British wild roses and also the first to come into bloom - sometimes in mid-May - and now it has come back into bloom in a hedgerow here at Wolsingham in Weardale.
There's been a lot in the press recently about the heat-wave inducing spring flowers to produce a repeat performance in October but it's not really that uncommon. Primroses, for example, quite often produce a few flowers in early autumn. For any species whose flowering is triggered by daylength, the hours of daylight are more-or-less similar now to those that the plant would have experienced in spring, so it's just responding weakly to the environmental stimulus that switches it into flowering mode. Spring-blooming wild flowers are more likely to produce an autumn encore if they experience in growth check in summer - maybe drought or low temperatures - that's followed by favourable conditions that allow resumption of rapid growth in late summer. I've noticed this particularly in some trees after a summer drought - somewhere I have some photos of rowans producing flowers alongside ripening berries in late summer, when rain after a drought has triggered a resumption in growth.

4 comments:

  1. That explains why my Wallflowers have new blooms! The Rose is beautiful.

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  2. Thanks for the explanation, Phil. Our primrose conundrum is solved!

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  3. Hi Toffeeapple, the rose hips are attractive too they ripen to deep purple and then turn black

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  4. Hi Graeme, we've got wild strawberries flowering and fruiting in our garden at the moment...

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