Garden blogs

Green hay experiment a spectacular success

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I feel really lucky

I’ve had a life-long passion for plants and look where I’m working – a national botanic garden.

Even better though is that by working at this particular national botanic garden, I have a chance to practically show how to conserve wild plants and to inspire others to do the same.

A great example is the use of green hay.  Since the Garden opened in 2000, two meadows on our Waun Las National Nature Reserve have been gradually transformed into wildflower-rich hay meadows. All we did was cut the meadows once a year in mid-late summer and remove the hay. This gradually lowered the fertility of the meadows while the parasitic yellow rattle flower  sucked the life out of the tall, coarse grasses that once dominated.

This created space for a wonderful range of wildflowers to find their way into our fields – we didn’t introduce anything.

Over the past 10 years, the likes of Plantlife and James Roberston – of the late lamented Natur Cymru – have been advocating the use of green hay to accelerate this change. So, in August 2016, we cooked up a plan to try this out on two fields on Waun Las that were species-poor – Cae Waun and Cae Derwen which were dominated by big bulky grasses like meadow foxtail, cock’s-foot, Yorkshire fog and rye grass.

Using Plantlife’s simple instructions, we cut the two receiver fields in the morning, removed the cut grass and then cut the two wildflower-rich hay meadows – Cae Trawscoed and Cae Tegerianau. Farmer Huw Jones then spread this fresh green hay onto Cae Waun and Cae Derwen within a few hours then went over the fields with a muck spreader, mulching up the hay and spraying it out of the muck spreader. On Cae Derwen, Huw also scarified half the field with a tyne harrow before the green hay was applied – that was all the time he had. Scraping the ground should help seeds find their way into the soil.

And then we waited.

2017 – lots of yellow rattle flowered on both receiver fields but not much else changed.

2018 – grass height and dominance fell dramatically in both fields. Lots of knapweed, plantain and some eyebright. One spotted orchid.

2019 – 200+ greater butterfly orchid, 50+ common spotted-orchids, a few heath spotted-orchids and one southern marsh orchids; two patches of whorled caraway, a specialist of southwest Wales; abundant yellow rattle, red clover, field buttercup and sweet-vernal grass, frequent knapweed, greater burnet, bird’s-foot trefoil and eyebright. Wow!

But how have these orchids appeared so quickly? We need help to explain this.

The Hardy Orchid Society say it takes 3-4 years for wild ground orchids to establish themselves. Orchids need the right kind of fungi in the soil to allow their seeds to germinate. Was the fungi there already? Other meadow experts have suggested the orchids were already there, laying dormant underground. But how long can they do that for? These meadows have had no visible orchids (we have been looking) for more than 20 years.  Did it help that we haven’t fertilised these fields for over 20 years?

In the past three weeks, news of this spectacular transformation has spread. I’ve taken large groups from the 49 Club, Carmarthenshire Meadows Group and Carmarthenshire Council to see what we’ve done. We’ve had requests for green hay from the National Trust, Abergwili Secret Garden and from members of the Carmarthenshire Meadows Group who’ll now be carrying out a countywide green hay experiment over the next few years.

We’ll also be converting another pasture to green hay – Cae Gwair, a large flat field at the entrance of Waun Las NNR, and a field that is more accessible for Garden visitors than Cae Derwen and Cae Waun. We’ve just done a botanical survey of Cae Gwair to get an idea of what’s there now, and I now can’t wait to see how quickly this transforms, I hope, into an orchid-rich paradise.