Blog-Yellow rattle, March 2017
Another growing season is nearly upon us, with several meadows which have been sown with yellow rattle. Plenty of unknowns still, but a pattern is beginning to emerge.
- Light land: broadcast yellow rattle before the sheep leave the field in autumn, seed rate 1g yellow rattle to 10m2 ( 400g/acre). It may be possible to add in seed of other species at the same time.
- Heavier land: grass in fertile fields / valley bottoms has the disconcerting habit of growing even better if it is power harrowed or roughed up without a much heavier yellow rattle seed rate. Only ploughing, inverting it completely seems to slow it up. Thus 1g yellow rattle to 2.5m2 is needed or 1.6kg/acre. Hence the idea of cultivating strips across the field so that you sow 1 strip in 4, reducing the cost by 75%. The yellow rattle has to be sown and well established before the other species are added, either as seed or as 9cm pots.
Trials in 2016 included:
a) 9m strips on light land (sown autumn 2015)where there were already 10 + species of wild flowers. Great results in 2016. This was sheep grazed in the autumn.
b) 9m strips on heavy land (sown autumn 2015) which looked good in June 2016, but was overwhelmed by the grass by the autumn. It was not possible to graze this field in the autumn, so I expect this field will be back to square one by this spring.
c) Our own trial at home where yellow rattle was broadcast in patches and horse grazed in 2014, with a couple of 3m strips rotovated through the meadow the following year for a wide range of additional species which were collected locally. The soil here is gravelly clay. All going well here, yellow rattle spreading well, but a fair bit of dock control needed as the rotovating brought quite a lot of dock seed to the surface. This is one of the risks you take when disturbing/rotovating old meadows.
I will be reporting on these three situations and no doubt others when I get round to visiting them in June.
Last day of May. Yellow rattle is in flower.
Yellow rattle is turning into a sort of wonderplant in that it reduces grass growth so that wild flowers can flourish. Our field is now full of yellow rattle coming into flower. The grass height is only 10-15cm high where yellow rattle is well established, otherwise it is 30-40cm high. It is clear from quite a distance where yellow rattle is active.
We have also sown yellow rattle in our churchyard where we have a fine array of old grave mounds which of course we cannot mow. Nearby, there is a wonderful area full of primroses and meadow saxifrage and some tough old grasses like cocksfoot. Well, the yellow rattle is getting its teeth into the cocksfoot which is great. As in our little meadow at home, yellow rattle is coming into flower. After a few warm days, we are now back in quite low temperatures with an unpleasant wind. Roll on flaming June!
20th April 2016
I inspected our small meadow this morning. The yellow rattle is starting to appear. Just! It is best to wait a couple of weeks and then it will be easy to see.
I had a discussion about mowing regimes last week which led to the following:
We usually think about cutting meadows at the end of the flowering period in late July. However, there is another regime.
Cut when the growth is well over the ankles and again sometime towards the end of May. Don’t bother to collect as in the spring there is enough biological activity for it to disappear, mainly thanks to little insect shredders! If the cowslips can be avoided, they will produce seed and help spread the cowslips quicker. This early cutting also helps to keep lesser knapweed under control if it becomes too dominant.
Cutting part of the area early will double the length of flowering , nectar etc. The uncut area will run out of steam around mid July, and the area which has been cut early will then recover and continue flowering right through until early September. The whole area needs then to be cut and collected.
12 April 2016
At last a warm day. The biting cold wind has gone (for now at least!) and sowing time for wild flowers will soon be upon us. It is never safe to sow before the blackthorn has finished flowering. It is in full flower with us now and we need some warm days to dry up the ground after the soaking we have received in the last few days.
I inspected the small clay area which I sowed last autumn. The front runners, oxeye daisy, common sorrel, ribwort plantain, self heal and yarrow were looking good and there were new arrivals - birdsfoot trefoil and ladies bedstraw. The other species will be along soon enough. I went searching for yellow rattle, the grass parasite which controls grass growth, but no sign yet.At last a warm day. The biting cold wind has gone (for now at least!) and sowing time for wild flowers will soon be upon us. It is never safe to sow before the blackthorn has finished flowering. It is in full flower with us now and we need some warm days to dry up the ground after the soaking we have received in the last few days.
I inspected the small clay area which I sowed last autumn. The front runners, oxeye daisy, common sorrel, ribwort plantain, self heal and yarrow were looking good and there were new arrivals - birdsfoot trefoil and ladies bedstraw. The other species will be along soon enough. I went searching for yellow rattle, the grass parasite which controls grass growth, but no sign yet.
Blue skies and warmer days may make you itch to get out and sow your wild flower seed, but the blackthorn has yet to flower, although it may be just starting. The blackthorn winter, the name given to the period when blackthorn is in flower, is often cold and wet and wild flower seed may rot if sown before this time. Once the blackthorn flower is over and the green leaves appear, you are much safer to sow.
I was visiting a site in Sussex on heavy clay last week, which was to be sown last autumn, but the rain never stopped and the land turned into a quagmire. It is now to be sown this spring. The area looked good with most of the perennial vegetation killed off with herbicides last year. Some grass had crept back over winter, so a final spray will be given and the seed will be sown probably in mid April. The farmer explained that he was not going to be as busy as he thought, because corn prices were so low that he was not going to sow any spring crops. “What’s the point of spending over £400 per hectare on a crop when you are not going to get back more than £350”. Growing arable crops on heavy clay is difficult at the best of times.
I had a quick look at a small area I sowed at home last autumn. The usual front runners were all their, ribwort plantain, oxeye daisy, sorrel, yarrow, self heal , and the odd meadow buttercup. The other species will follow in the next few weeks. I am particularly looking out for yellow rattle which will control the grass growth.”
December 7th 2015.
Patience in establishing wild flowers
This concerned a 17 acre field, sloping down to a valley, the top being heavy clay and much of the lower part being on thin chalkier soil. It was sown in September 2014 in good conditions. Last spring may have had quite a few blue sky days, but it was often cold and dry and as a result the seed germinated quite well on the heavier clay where the soil was able to retain moisture, but on the chalkier lighter land, the soil simply dried up and nothing germinated. It looked bare all through the summer months. I inspected it today and thanks to the remarkably warm autumn, everything is now germinating with small plants of self heal, sorrel, oxeye daisy, hedge bedstraw, kidney vetch, greater knapweed and so on. It just goes to show that you need to be patient!
An added point here is that many of these arable soils have been flogged to death over the years with continuous arable cropping. They have lost all organic content which is the vital agent which acts as a buffer against extremes of weather and temperature. As a result, seed may not germinate if the weather is difficult, but patience is usually rewarded, and I can hardly think of a single example where new seed has had to be sown.
My blog has been silent for a year. What has been going on?
Well, quite a lot. Last autumn I launched another book “Irreplaceable Woodlands” on the subject of managing ancient woodlands, with as you can imagine, lots of information about woodland wild flowers, their huge importance providing nectar for the woodland ecosystem and how to encourage them. This book like its predecessor “Where have all the flowers gone” has wonderful photographs thanks to Mike Bailey and Steve Williams. When I had finished this book, I realised just how much goes on in an ancient wood which I still wanted to write about, particularly all the comings and goings in and out of a wood. A wood really is central to the wildlife and landscape of a parish. This new book is going to be in the form of a diary and is quietly taking shape.
The Blog could be renamed Yellow Rattle blog, because almost everything of interest seems to include this remarkable parasitic plant, particularly in restoring wild flowers to old grasslands which have lost all their interest. Let me explain the wild flower restoration situation as it is today.
Converting arable land or existing grasslands to wild flowers.
This is where everything is killed off, a new seedbed created and new seed sown. The methods here are now relatively well known and there is a great deal of experience around the country as to how this works. Clean well consolidated seedbeds, autumn sowing, a last go at the weed seeds before the precious new seed is left on the soil surface, with a final roll if it is at all dry.
Restoring diversity to existing grassland.
We have 50 acres of old parkland in our parish which is fairly typical. It was sprayed with herbicides in years gone by, but the grasses are good with around a dozen species and occasional plants of ladys bedstraw or birdsfoot trefoil. It is important not to spray it all and lose the scarce flowers which have survived, especially if some of the remaining wild flowers are rather special. Another case is a field of Yorkshire fog where the grass is really strong, but the owner wants to get back the wild flowers. The question was, how do you restore wild flowers to these areas.
Getting yellow rattle established. This is the first stage. Without yellow rattle the grass will be too strong for the wild flowers, so after many failures, we have realised that the best method is to get yellow rattle established first, then add the wild flowers. Given the huge range of soil types, the detail of how you add yellow rattle varies enormously.
Light/chalky soils: we have been able to spin on yellow rattle seed before the sheep leave the field, so that they tread it in, with seed rates of 1g yellow rattle to 10-15m2.
Heavier soils: A different approach is needed on stronger land as the powerful grasses overwhelm the yellow rattle seeds. However, yellow rattle spreads well once it gets established, so we have now moved to cultivating strips across the field with a heavier rate of yellow rattle seed being used, 1g yellow rattle to 2-5m2. Width of strips needs if possible to match the available cultivating equipment, so multiples of 3m are popular. We have a number of projects nearby where strips have been made this autumn, so we will be watching these closely to see how they perform. Some strips which were disced, power harrowed and sown with yellow rattle last autumn have worked well. Once the yellow rattle is established, we can add in the other species.
A few diary entries may be of interest.
June 29th. We went off to Somerset where there is a group of outstanding old meadows in the west of the county. One of these was a small arable field, where green hay was strewn a few years ago. We wanted to add in devilsbit scabious which can be tricky from seed, so the owner collected seed from her other meadows and we grew on 500 x 9cm pots, which we planted out a few years ago. We looked at the field where we had done all this. The wild flowers generally were fantastic but the devilsbit was pretty scarce. The reason was that even though we used well grown 9cm pots, the grass was too strong, and the yellow rattle was not well enough established.
Even where you think you have a sturdy 9cm pot, the grass growth needs controlling with yellow rattle.
July 9th. Training course at Wakehust Place, Sussex, an outpost of Kew and home of the Millenium seed bank. This was all about collecting seed, seed quality, storage etc but we also looked at a meadow which they had been restoring, called Bloomers Meadow which is within the Arboretum. There was a huge population of yellow rattle here and dyers greenweed, a locally distinctive plant had been added in 9cm pots. It had established really well. Reason why? Yellow rattle had more or less eliminated all the grass.
Yellow rattle is essential when wild flowers from 9cm pots are planted.
July 2nd. I have been advising on a meadow in the Pang valley in Berkshire which was almost completely derelict, unmanaged and full of nettles only a few years ago. It is now being actively managed with a late hay cut being taken with grazing later in the autumn. Yellow rattle has been established and what is fascinating is the way that it has weakened the grass leading to a number of species reappearing: tufted vetch, selfheal, fleabane, lesser knapweed, oxeye daisy, purple loosestrife and red clover. I have no doubt that more species will appear. We discovered a single clump of the now scarce greater burnet a couple of years ago and seed was collected and grown on with 20 or so plants being planted out. The colony is expanding nicely. I don’t know where the nearest population of greater burnet is, probably many miles away.
Yellow rattle will control the grass and this reduced competition will help other species to recover.