Thursday, June 26, 2014

Weeding the Countryside?

Spotted orchids en masse, I wish I understood how and why they spread

Following on from my last post about weeding the garden, specifically a very naturalistic planting (which some folk might think was a mass of weeds anyway), the next task has been to try to do some vegetation management in the fields we have.

Before I talk about that, I've spent about an hour today on my new method of controlling cow parsnip/hogweed – Heracleum spondylium. In some ways this is a wonderfully architectural biennial, with very impressive foliage, we might even pay good money for it, but it seeds so aggressively, and even little seedlings can be so difficult to get out as they have such deep forked tap roots. So I keep them in the outer fringes, not even allowed in the wild garden, although I am only too happy to let them flower. However it will also produce mature seed within 10 days of the flowers dying. So you have to be on the ball. Today, I cut off the flower heads and injected the hollow stems with herbicide. Should do them in without harming anything else with any luck. Got the idea from how they deal with Japanese knotweed.

Anyway, the fields, which have in parts, a very interesting flora, the wetter it gets, the more dominated by rushes and sedges, hardly any grass, with Pulicaria dysentrica, Potentilla anserina, and much else, some great patches of ragged robin, Lychnis flos-cuculi and spotted orchid, Dactylorhiza fuchsii, in ever greater numbers every year. The diversity is pretty amazing, but it is very vulnerable to be overtaken by the next stages in succession - leave it ten years and it would an alder/willow forest, interesting but not the same.

To keep it in its current very biodiverse state, and even improve it, needs extensive management, i.e. operations that you apply either to the whole thing at once, or to multiples of plants. It is very different to 'gardening' as such. The timing of mowing, or whatever else you do, can make an impact on the species mix, but the effects are complex, subtle, and take time to take effect. One of the papers I was reading suggested that a mid or late season cut maintains the flora, an earlier one will have more impact on the species, mix, and make a bigger impact on the more competitive species. Because the Pulicaria (fleabane) flowers so late, September, we don't mow til really late.

In parts there is meadowsweet, Filipendula ulmaria, which tends to exclude other species, and is the immediate next stage in succession, and so there is a need to control it. It also tends to work in concert with greater bindweed, an alien weed species which can smother other plants with a vengeance. The bindweed runs along the hedge, and climbs up the meadowsweet and then out into the grass. So out with the brushcutter to take down all the meadowsweet which runs along the hedge.

Trying to find out whether this really is a good course of action was difficult. Actually finding out much about managing semi-natural vegetation like this is surprisingly difficult. Googling brings up lots of research papers, most of them seem to be studies undertaken in Czech or Poland, so not sure how useful they are for here. In other cases there seems to be a lot on the conservation of meadowsweet, rather than a concern for its impact on other species.

One thing which is definitely a problem is the bramble, who needs invasive aliens when you have brambles? In our part of the world they grow almost all the year round, reaching out from the hedgerows rooting and running and before you know it they are shading out everything beneath them. But a small area of rooting can support a lot of top growth. They are difficult to deal with by mowing, as they get tangled up with the mower. So, I plan to cut them all off with secateurs at the base, then mow and herbicide spray the regrowth, which will be limited to just a few rooted growth points. Should do them for the next few years.

The DR, our main heavy grass cutter, with a fallen tree behind which acts as a bridgehead for brambles which come out of the hege (right). We might leave the tree as it is still alive and has lots of fruit (sloes).
Two years ago, I did a post on Adding to a Meadow. I can report back that we seem to have success, all the species added seem to be present, a few of the Trollius flowered and some of the Polemonium this year too. Plenty of foliage of the added species is there too. Progress will be slow as competition is so intense, and it will be interesting to see if we get any spreading.

With more and more people managing little bits of land like this, an acre here, a quarter hectare there, the need to understand how to do extensive management is going to grow. It is a different kind of gardening.

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1 comment:

Roger Brook - No Dig Gardener said...

It would seem that naturalistic plantings and creation of 'new ecologies' are with plants of the world.It was certainly true of William Robinson who used some significant none-native plants.
Personally I am extremely comfortable with this and approve of plants crossing borders but I wonder how those gardeners who limit themselves to native plants see the use of prairie planting in the UK.