Further Green Hay experiments at NBGW

If you’ve been following this website for a couple of years, you might remember this post from July 2019: https://carmarthenshiremeadows.com/2019/07/25/visit-to-the-national-botanic-garden-of-wales-to-see-results-of-green-hay-experiment/

In summary, on that occasion a group of CMG members were shown round parts of the Waun Las National Nature Reserve (part of the NBGW estate) by the Garden’s Head of Interpretation, Bruce Langridge.  Bruce showed us two fields, (Cae Waun and Cae Derwen) hitherto of little botanical interest, onto which hay, cut only from the species-rich meadows on the Waun Las reserve, had been spread in 2016.  We were all amazed at the range of species that had appeared in only 3 years on these receptor sites.

CMG at the National Botanic Garden of Wales

This summer, we were keen to arrange a return visit to see not only those fields again but also another previously botanically unremarkable receptor filed where the experiment was repeated using some of the Waun Las hay cut in 2019. So, last Friday (July 2nd) members of CMG were shown the field (Cae Gwair) only 2 years after the green hay was spread.

Cae Gwair on the Waun Las NNR

We saw in flower great butterfly orchids, whorled caraway and, although they have of course finished flowering now, Bruce told us that very surprisingly, bluebells have appeared in this field for the first time. We also saw how patches in this (and earlier receptor fields) look different from each other, due may be sometimes to local differences in soil conditions but also sometimes to a particular combination of seeds falling off the machinery depending upon what it had been used for previously. On the new field there is one area with a lot of Cat’s Ear which isn’s so obviously elsewhere in the field for example, probably because of where the spreader was being loaded up. In a wetter patch in one of the 2016 hay-spread fields, a patch of Greater Burnet (which likes the wetter soils such as that in the marshier Cae Trawscoed) is quite obvious.

Great Butterfly Orchid

Given the success of this technique, there are plans to use green hay from NBGW at some other nearby sites including some managed by the National Trust – but this method does depend on donor and receptor sites being fairly close together as the hay has to be spread within a few hours or it will heat up too much for many of the seeds within it to survive. For sites further away, brush harvested seeds could be used – but that’s another story…….

Bruce and Laura from NBGW

It was a fascinating and useful visit. We are very grateful to Bruce and Laura from NBGW for giving up their time to show us round. The visit also enabled 18 of us from CMG the first opportunity in what seems like a very long time to meet up (socially distanced) face to face and exchange ideas, observations and views – which is the whole point of the group.


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