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.


SUPPORT THIS BLOG
I write this blog unpaid (of course) and try to do two postings a month, to try to provide the garden, wildflower and plant-loving community with information, inspiration and ideas. Keeping it coming is not always easy to fit into a busy working life. I would very much appreciate it if readers would 'chip in' (as we say in England) and provide a little financial support. After all, you pay for magazines and books, and it is only for historical reasons that the internet is free. Some money coming in will help me to improve quality and frequency, and to start to provide more coherent access to hard information, which I know is what a lot of you really want. So – please donate now!! You can do this through PayPal using email address: noelk57@gmail.com
Thank you!

********
If you like this blog, why not check out my e-books, which are round-ups of some writing I did for Hortus magazine back in the early 2000s, along with an interview with the amazing Beth Chatto. You can read them on Kindle, or Kindle packages for smartphones or the computer. You can find them on my Amazon page here. You will also find my soap opera for gardeners - currently running at eight episodes.


Sunday, June 1, 2014

On the attack - early summer weeding



A day spent in the garden – weeding. Having been away for 2 weeks there is a lot to do at this time of year. This is the crucial period, to stop things seeding. It is also a very good time to evaluate what we're doing. And – more generally to reflect on what naturalistic planting is, and how realistic a proposition it is.

I must admit I have a slightly bipolar relationship with the gardens – sometimes revelling in its rich assortment of plantlife that very largely looks after itself (and wildlife, like the almost deafening sound of bumble bees feeding on Symphytum caucasicum), and at other times feeling almost despairing at holding the ring against an incredibly aggressive weed flora. I sometimes worry that if I don't get on top of things, grass and nettles could overrun everything in no time at all.

The planting is largely made up of robust perennials which can indeed look after themselves: some of them stay more or less the same size, others spread out to form solid clumps, some seed around and are gradually insinuating themselves themselves all over, some seem to get overwhelmed – either by stronger-growing neighbours and/or weedy spontaneous species.

The best way to keep unwanted weedy wild species at bay is to have as complete a vegetation canopy over the soil as possible. A lot of my planting is a lot more dense than most people's. Eventually, I aim and intend that it should be as dense as natural vegetation - but with a composition which is aesthetically pleasing for as long as possible. At this density, some garden plants have a different form to how they are grown more conventionally - for example many clump formers like geraniums and astrantias form long stems which wend their way through other plants. This method of growing does not suit species with ground level foliage, like asiatic primulas, which will not tolerate taller things growing above them; primrose/polyanthus/oxlips though seem ok, as their become semi-dormant in summer and don't mind being crowded and overshadowed.

We have an incredibly aggressive weed flora: pasture grasses, creeping buttercup, stinging nettle, dandelions, wood avens. My recent visit to the USA has illustrated just how successfully some of these have joined/invaded the North American flora – and yet not a single species of North American origin has become a problem alien in Britain (a few have, possibly, in mainland Europe). Weeds are a problem because if not dealt with they would quite quickly out-compete almost all garden perennials (and many natives too).

Our garden gets high rainfall, the soil hangs on to it, and we have a very high level of fertility, so if a plant likes it here, it grows incredibly vigorously. Such a situation is exploited most effectively by the species which can make the most of the resources available – which varies enormously. Those which can turn nutrients into leaf and root the fastest tend to be the most troublesome.

 But what makes a plant a weed? Such a question leads onto my idea of the hierarchy of weeds.
  • Public Enemy Number One(s)
  • Those to eliminate as much as possible, but not necessarily totally
  • Wild Plants which are not really Bad Weeds, but Which I Don't Like
  • Minor nuisances, usually tolerated
The list can be cross-referenced to the different parts of the garden, where different standards apply:

The Wild Garden where Those to eliminate as much as possible, but not necessarily totally can be given plenty of scope (because the inhabitants of the wild garden will, for the most part, keep on top of them).

The Borders – where Minor nuisances, usually tolerated, are indeed tolerated, as well as a certain number of Wild Plants which are not really Bad Weeds, but Which I Don't Like are also allowed to get away with it.

Vegetable Garden, areas for annuals and test and nursery beds – have to be kept clear of almost anything and everything.
    Public Enemy Number One(s)
There are a few (very few) species which are so effective at utilising nutrients and turning them into growth which suppresses all else that they just have to go: dug out or Rounded-upped (or otherwise herbicided). The Stinging Nettle tops the bill. This is a very worrying plant, not just because it will get the better of just about any non-woody plant but because it is capable of slowly smothering the entire British non-forest flora. L
isten to this BBC podcast . Fed by nitrogen pollution, septic tanks and over-use of fertilizer, I have seen nettles advance over more diverse floras here since we moved – in places where they must be being fed by nitrogen pollution (caused by car exhausts primarily). It was worrying to see them in the Pacific North-West recently too. Mind you, they make nice soup!
Cocks foot grass (Dactylis glomerata) is another, an aggressive tussock former which eliminates all competition.

Those to eliminate as much as possible, but not necessarily totally
 The Creeping Buttercup (Ranunculus repens) is a good example here, which flourishes on our damp soil. It makes establishing anything difficult, and can cover ground with frightening speed. However I cannot help but be charmed by its yellow flowers at this time of year, which when dotted around between and beneath other plants are undeniably part of the visual mix here. The fact is, most the stuff I grow gets bigger than it does, and so it gets out-competed, so it is simply not a major issue for the borders and certainly not the Wild Garden.

Wild Plants which are not really Bad Weeds, but Which I Don't Like
Horrible smelly Stachys sylvestris is one, can't remember its English name, runs but not a real nuisance, if it had better flowers I would have no problem with it. Ditto Wood Avens (Geum urbanum). To be honest, i can't see it out-competing most of the things I grow, as it does not spread but stays very tight, it just seeds so such, and doesn't earn its keep, but there is no way I can do much more than keep its numbers down. There is a grass too (not very good at IDing grasses), I think it is Agrostis stolonifera, which seems to get everywhere, but it is so light and it seems very uncompetitive that I can't get too overexcited about it. Trouble is, these are not problem plants, but they seed so much, and in quantity could become competitive against desired plants in spring. If the worst comes to the worst they can be hoed off in dry winter weather (on the rare occasions we have it) or Rounded-Upped if they are growing en masse at this time. Most native weedy species start into growth before non-native perennials, which is part of the problem as it gives them a competitive advantage, but it does mean you can see them and eliminate them.

Epilobiums/Willowherbs too, but they are quite easy to pull out, or hoe off the seedlings. They don't compete and as they canopy builds up they lose their habitat.

Plants that some people think are weeds but I don't (at least in perennial plantings).
Hairy Bitter Cress, little speedwelly things,

One final point, because the garden vegetation is very dense, which is one of the visual delights, plants tend to support each other - weeding or stepping into plantings can cause gaps, plants to collapse - and they can take some time to pick themselves up again and sort out their positions again. Something to think about, when we have a garden opening coming up, but then if you don't deal with those creeping buttercup plants now they'll seed and spread.



SUPPORT THIS BLOG
I write this blog unpaid (of course) and try to do two postings a month, to try to provide the garden, wildflower and plant-loving community with information, inspiration and ideas. Keeping it coming is not always easy to fit into a busy working life. I would very much appreciate it if readers would 'chip in' (as we say in England) and provide a little financial support. After all, you pay for magazines and books, and it is only for historical reasons that the internet is free. Some money coming in will help me to improve quality and frequency, and to start to provide more coherent access to hard information, which I know is what a lot of you really want. So – please donate now!! You can do this through PayPal using email address: noelk57@gmail.com
Thank you!

********
If you like this blog, why not check out my e-books, which are round-ups of some writing I did for Hortus magazine back in the early 2000s, along with an interview with the amazing Beth Chatto. You can read them on Kindle, or Kindle packages for smartphones or the computer. You can find them on my Amazon page here. You will also find my soap opera for gardeners - currently running at eight episodes.