Tuesday, 30 June 2015

Eliminating nettles and ground elder to make a new grassed garden without digging



Ready - steady - wait… wait even longer - go
I still started too soon!

Project director
Ground Elder   Bishop weed 
Do not be too keen to begin any new weed control project until the weed is sufficiently luxuriant to drink up your Roundup (glyphosate). It is totally useless to zap your perennial weed as soon as it pops its little head out of the ground.
I have waited until early May. It would have been even better to have waited until June!
It is hugely detrimental to the success of herbicide based weed control to cultivate the soil before spraying and a complete waste of your energy and usually counter productive to cultivate afterwards too. The weed must be intact when you spray.

I have a new project. Many of you know that two years ago I took over maintaining Cathi’s garden. No not the mowing nor putting up netting to contain her hens. Although I cut her side of our shared hedge I have previously shied away from the 20 foot high 100 yard long over-grown hedge that borders the road. Not cut for ten years it was badly overgrown. 

I do not take much credit for cutting the hedge down to six foot high. That honour falls to Peter Williams who brought his chainsaw and worked his eight hour way along it. With a little help from my son I dragged the heavy prunings into the garden. 
Two months later Pete and myself had a wonderful day burning a huge bonfire and as I have previously reported gained fourteen barrow loads of wonderful soil enhancing charcoal. For myself - sorry Cathi.

To facilitate easy of mowing I had in the previous year sprayed off a four foot strip of lawn at the base of the hedge within Cathi’s garden. I  continue to plant and develop a mainly herbaceous mixed flower border in place of the dead turf. No digging of course!
On the roadside of the hedge a seven foot wide strip had had no maintenance at all. A further four foot was roughly mown by Mike from across the road. 
Needless to say that within the base of the hedge and on the outside of the garden it was full of perennial weed. It was mainly ground elder and nettles that gained five foot high every summer.

A further detail relevant to the project was that there were sections of the hedge where elms had died several years before when infected by Dutch elm disease. In classical fashion when elms grow beyond shrub size and start to become trees the bark beetle brings in the deadly fungus. There were several large gaps in the newly cut back hedge. Peter and I plugged the gaps with beech and yew and left some dead elm trunks to support climbers that would give rapid screening.

First spray.
Impatient I could wait no longer and sprayed in early May with my knapsack sprayer. Ground elder is a difficult weed and one application will not be anywhere near enough to eliminate it. My experience on the village plot suggests that it will take at least a year and probably eighteen months before the ground elder is completely eliminated.
Nettles are not terribly well controlled with glyphosate and I wanted to try MCPA. I did a little ‘trial’ and sprayed a section with just MCPA and the rest with a glyphosate/MCPA mix which I have previously found to be a very effective combination against other perennial weeds.
MCPA alone will not kill grasses and gardeners use it to eliminate weed and keep any turf. I have other fish to fry and this detail was not significant to this particular project. Not only was there virtually no grass but I want in due course to replace any coarse grass with a finer grass mixture.

Both recipes quickly knocked back the nettles. (It was the MCPA ‘wot did it’ ). A month later  the tops of  all the weeds were completely killed back by the glyphosate/MCPA mixture but the MCPA-only had not done very well against the ground elder. 

I did not expect that. I do know how effective MCPA is against nettles and many other perennial weeds. Different weeds vary in their sensitivity to herbicides and for the rest of this project I will just stick to glyphosate.

When the afore mentioned  month had elapsed after my first spray although growth had been  slightly checked with the MCPA-only treatment it now had an even greater receptive leaf area to weedkiller.  I sprayed it with glyphosate-only. It was too soon to spray the successful other section.

This meant that two months after starting both sections in the comparison that yesterday at the end of June both had received exactly the same total amount of herbicide (one in the single double dose and the other in two separate doses).
The two treatments  are now out of ‘sync’ and this morning the now regenerating  once sprayed area has been sprayed again with glyphosate. It took 20 minutes.  

The total time spent spraying since the start of the project is under two hours.

Technical details
The commercial glyphosate was the normal 360gm/litre strength diluted at 1 part in 50. The MCPA was Agritox, also 1 in 50. I sprayed just short of run off on a very still morning. I took me one hour to apply the first spray.

A different approach to this blog post.
The project has just started. Heaven knows how it will finish! I am intending to create a feature composed of bulbs, wild flowers and garden annuals and herbaceous perennials set in fine fescue grass. My normal ‘naturalistic’ methods exclude grass so it will be a new experience for me. I intend to report at appropriate intervals in future posts. You will be able to synchronise your future reading by clicking in my theme column

The priority for this Summer is to completely kill the weed although it might take a little longer. The fact that the weed looks completely dead now gives the wrong impression. It will be sprouting again soon!
If you have a similar overgrown area it is an excellent time to start now on the first of July.

Addendum. Glyphosate will kill both nettles and ground elder. Ground elder will take much longer to be eliminated than nettles. Once all the persistent vegetative parts of the ground elder are killed it will be gone for ever unless allowed to spread in from adjacent land or reintroduced by careless planting. Nettles will return from seed if the cleaned plot is neglected.

Picture post. The project’s pictorial progress

From inside the garden you can see the height of the hedge last summer. Although the project was not yet planned I had started to cut back some trees.

Peter’s prunings  to be burnt 

The next week we gapped up with yew and beech where the hedge had been killed by Dutch elm disease. This Spring the new plants have needed generous watering. The dead wood has been left in for temporary screening and to support climbing plants 
Peter always leaves his projects tidy. You can’t imagine the debris we cleared. At this stage in late January there is no indication of the dormant bishop weed (ground elder) and nettles. This is the first time that anyone has enjoyed the snowdrops in the last ten years. They will be back even stronger next year. As a surprise for Cathi and planning for the future I had planted some native daffodils ‘in the green’. 
I had rescued the native daffodils from the hedgerow across the road. They had been deposited there by recent roadworks that had disturbed the grass verge 
Although not ideal to transplant daffodils in the green they will fare better than being  totally smothered by a hedge

Mid April. Still too early to start and should I spray I would have to avoid the daffodils

Early May was a little early to spray. The weed would be more receptive a few weeks later. I sprayed anyway. See how the weed infiltrates the hedge. Careful downward direction of the spray head ensures there will be zero damage to the hedge. 
View from inside the garden just before first spray
Two weeks after spraying with glyphosate/MCPA  the weeds are looking sick. The nettles have been killed by both treatments but where the spray was just MCPA ( the area in the middle) the ground elder has scarcely blinked   
A month after spraying  (it was then early June) the MCPA-only bishop weed was starting to recover. As a consequence I sprayed it with glyphosate. It was still too early to respray the glyphosate sprayed area where the weed was still not yet re-sprouting

July 1st the roles are reversed and the two treatments are out of step. After two months the glyphosate/MCPA mix needs its first respray (with glyphosate only this time!) Although the area sprayed with MCPA and glyphosate on separate occasions  looks dead it is not. It will re-sprout very soon!

Progress of the hedge at the end of June. The sweet peas are doing very well and will cover the dead wood. By late August they will be over. Plenty of time to respray any ground elder I have missed

The conifers were completely overgrown last year by the hedge and were completely suppressed and dying. Early last Summer I had opened them up to the light. They are now not only visible but thriving. 
Oh dear, the hedge now needs trimming!
I actually grow variegated ground elder in Bolton Percy cemetery garden. This picture of it brightening up a heavily shaded cemetery was taken in London on the occasion of London Squares Open Gardens

You can read about how I cleared the village plot of ground elder here
The story of preparing charcoal from the prunings is here

I have posted part 2 today

6 comments:

  1. Roger your posts are always very informative!

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  2. That looks like a big job and one that is trying too. I am always battling weeds like ground ivy. If I use Roundup I swear the weeds laugh at me. I have been trying repeatedly to get rid of a variegated ivy that came in a florist arrangement. How it got outside I don't know, but it has been in the garden for years. This year I tried roundup on it and it just laughs at me coming back after every application.

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    Replies
    1. Glyphosate is pretty useless as you have found Donna for common ivy!
      Best to keep cutting it to the ground until it is gone.

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  3. That's some job and one that needs a strong will Roger. Thankfully ground elder isn't an issue in my garden and the nettles seeded from next door's wild patch are dealt with as and when I remember with which ever weedkiller I have at hand and that seems to keep them at bay. I daren't neglect it for a few months, then I suspect I'd have a bigger job on my hands!
    Well done to you all for taking on such a big job for Cathi.

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    Replies
    1. I love this type of project Angie. Especially when I can do a post about it!
      Roundup does kill nettles as I expect you have found Angie but it usually needs a second dose and even nettle seedlings put up a fight!
      The only hard work so far was cutting back the hedge and burning it. I gave it its first new cut today and did get rather warm.
      The actual elimination of the weed is easy providing you are patient.

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