The Flower Calendar
When wild plants flower in France, and how that calendar shifts with warming temperatures.
Phenology, the study of seasonal cycles in nature, is one of the most sensitive indicators of climate change. Across France, thousands of citizen observations record each year the first flowering dates of wild plants. Visualised on a circular calendar, these data reveal the beauty of natural rhythms and, in their slow drift, the quiet imprint of warming temperatures.
The calendar brings together twelve wild species common across France: from blackthorn and wild daffodil, among the first to flower at the end of winter, to heather, which opens in late summer. For each species and each decade, the date shown is the median day of the year on which its first observation was recorded, computed from several thousand GBIF occurrences per decade; the range shown around that date (10th to 90th percentile) gives a sense of its year-to-year variability.
Show the data as a table
| Species | 1970-1979 | 1980-1989 | 1990-1999 | 2000-2009 | 2010-2019 | 2020-2026 | Shift |
|---|---|---|---|---|---|---|---|
| Blackthorn Prunus spinosa | April 1 | April 6 | March 4 | March 5 | March 11 | March 6 | −26 d |
| Wild Daffodil Narcissus pseudonarcissus | March 21 | March 14 | March 3 | February 26 | February 25 | February 17 | −32 d |
| Dandelion Taraxacum officinale | May 2 | May 3 | April 17 | April 1 | March 23 | March 7 | −56 d |
| Poppy Papaver rhoeas | April 8 | April 22 | April 6 | March 25 | April 11 | April 16 | +8 d |
| Foxglove Digitalis purpurea | March 29 | April 5 | March 6 | February 24 | March 7 | March 30 | +1 d |
| Lavender Lavandula angustifolia | April 7 | March 29 | February 23 | February 24 | March 3 | March 31 | −7 d |
| Cornflower Centaurea cyanus | May 13 | April 22 | April 19 | April 2 | May 13 | April 28 | −15 d |
| Heather Calluna vulgaris | March 9 | March 9 | March 5 | February 28 | March 12 | March 18 | +9 d |
| Lily of the Valley Convallaria majalis | April 6 | April 11 | April 5 | March 21 | April 9 | April 13 | +7 d |
| Dog Rose Rosa canina | March 30 | April 14 | March 21 | March 2 | February 26 | February 22 | −36 d |
| Crocus Crocus vernus | February 24 | April 7 | March 31 | March 10 | March 22 | February 22 | −2 d |
| Wood Anemone Anemone nemorosa | March 29 | April 3 | March 8 | March 5 | March 18 | March 10 | −19 d |
Data sources
Download the prepared data: phenology.json (11.1 kB)
Files as the visualization uses them. Reuse remains subject to the licenses of the sources above.
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