Wednesday, 9 December 2015

Control of nettles and ground elder: Part 2

Part 1 followed the progress of 250 square metres of overgrown land between Cathi’s hedge and the road. To eliminate the ground elder will take up to two years. My eventual ambition is to convert the area to an area of flowers growing in fescue grass as if in a meadow. All without digging - of course!
I wonder if the folk who read Part 1 were troubled with nettles or ground elder? By the end of July both of my treatments did for the nettles. Even under the hedge where it was easy to miss them, by August the nettles were completely gone. There was little sign of them returning from seed but that good fortune may not continue. 
Continuing experience tells me that MCPA or its alternative 24D is very effective against both annual and perennial nettles and so is glyphosate but at a strong 1 in 50 dilution of commercial product

The continuing saga
My last post concluded with the resprays of regenerating weeds. As the two treatments were different, the timing of the resprays differed. The two treatments had been one area sprayed with a glyphosate/MCPA mixture the other with MCPA alone. The first treatment had been followed in early July with one more glyphosate application. The original MCPA sprayed plot was resprayed twice with glyphosate. The total amount of glyphosate and MCPA used was the same for each treatment. Both treatments I judged to be equally successful.

There was still plenty of weed at the end of the last post in mid July. The weed in the picture had been sprayed several days before it was strimmed
There were then two changes of plan! A week after the last respray Cathi's handy man intervened uninvited and strimmed the whole area. It certainly looked tidier! No harm was done as the leaves on one of the treatments were dead and the leaves on the other had already absorbed the weedkiller. Indeed the fact that the dead and dying tops were cut away made it easier to recognise new regenerating weed growth.  
You will remember that the plot area at the edge of the road had a four foot band of rough grass which was left unsprayed. It was not a great surprise that a forty foot length of it proved to also be full of ground elder. By August it had been allowed to become fairly luxuriant - as is necessary for effective control - and  was sprayed with MCPA. You will recall that MCPA, commonly bought as Agritox, is selective and does not kill grass. Regenerated ground elder in the grass sward was subsequently resprayed with MCPA in mid September. This grassy section will probably need two further applications next year to completely eliminate the ground elder.   

There was more ground elder growing in the grass strip than I had thought
At the end of July both treatments on the original sprayed areas were effectively at the same phase and had been equally successful. Although the job was certainly not finished! 
My story today starts there. For my continuing saga I will no longer differentiate between the two original treatments.

The nettles were all gone and nor was there much to see of the ground elder. Just a few clumps, perhaps from deeper roots that had not earlier emerged sufficiently to receive enough spray. These clumps were sprayed with glyphosate.

By this time the main problem was new weeds from seed. The new weed cover was quite light and quite honestly I just reverted to my normal routine and when I did my usual maintenance ‘spot’ glyphosate-spraying around Cathi’s garden just added the new area onto my spraying routine. The extra time was no more than ten minutes as my directed spraying only needed to cover the small proportion of the ground area where there were weeds visible. By mid November I had spent a total half an hour to have sprayed three times.

I had scattered some seed of forget-me-not for some Spring flowers next year There are too many and most of them have now been sprayed away
Typical weeds from seed that grew in the empty spaces

The same weed three weeks later
At the end of the year there are still ground elder roots present. If I disturb the soil surface I find small ground elder shoots just below the surface. Not everywhere but in a few significant places. They won’t emerge until Spring! My original advice still applies to not zap them as soon as they emerge but to wait until they make enough leaf.
The battle is almost won but it is important not to assume victory at this stage. Gardeners should not next year get complacent and plant perennials too soon. There should be no permanent planting until the very last ground elder is gone.

At the end of the season there were signs of ground elder regeneration. Because the ground elder is too small it is now too late to spray.

As you will see from the yellow patches of grass in November I have not told you the whole story today!

I small sneaky patch of ground elder and seedling epilobiums in October
On reflection the ‘ground elder’ in the picture looks a ‘dead ringer’ for a seedling elderberry tree. No matter, the elderberry is one of very few shrubs that are very easily killed by glyphosate
Cleavers is a common annual weed that germinates in October. Sprayed in late October it was in early December completely dead. To kill it was a high priority
More about nettles
The few nettles pictured today came from seed. There were no more than half a dozen when I took my picture in early November. It was NOT too late to spray them. My previous problem had been established perennial nettles and the new young nettles were the same perennial kind. 

New nettles from seed had sneakily arrived under the hedge

In my vegetable garden I have eliminated most weeds-from-seed problems by my minimum cultivation policy and by not letting weeds ever set seed (well almost). I still get a few seeded perennial nettles! Their seed must be able to remain dormant for a very long time. As soon as I spot them I pull them out or hoe them.
Some of you may have annual nettles Urtica urens. They can be a considerable nuisance in the vegetable garden. Try not to let them set seed. Keep the hoe going! If they are on an empty patch spray with glyphosate. You will need full strength 1 in 50 dilution of 360gm product. (The alternative MCPA might leave residues for up to a month). Although not perennial, annual nettles can be very persistent. 
I have known gardens with annual or perennial nettles sprayed with too weak a solution of glyphosate where nettles have been able to become badly established.

What about the rest of the project?
Well the cut back hedge certainly grew! It is quite amazing how quickly cut back shrubs and trees can regenerate as a result of their strong root system. I spent several hours cutting new growth back to keep the hedge narrow and not any higher. I was particularly severe on the horrible hornbeam, elderberry and hawthorn. The hedge must not get any wider The new hedging plants inserted into the gaps with the help of watering and fertiliser put on about a foot of new growth. It will be much more next year and I have already applied fertiliser for next season. As the new hedging plants grow I will whittle away at the original coarse wood.
All this hedge cutting is getting too much for me and for next year we have sourced a farmer who will keep it trimmed back very cheaply.

Viewed from inside Cathi’s garden in late November. The hedge is less of a screen than in Summer, there has been leaf fall and heavy pruning and the border is looking tired. Note the strong growth on the privet

Hornbeam is not my favourite plant and that ugly cluster of trunks on the right needs to go
You will recall that some of the trunks previously killed by Dutch Elm disease had been left in as a screen and support for sweet peas. The planted yew and beech have had a good first season
As to my ambition to create a flower border in grass this will be the subject of a new series of posts which will start this month. I have been a little disingenuous today because I have idealised my report to help gardeners struggling with a problem of ground elder control. Other things have been going on! Despite me telling you not to.

(You can now skip to the future to read about my continued weed control and more about planting)

Those of you with ground elder or nettles growing in grass need to read about MCPA

Last week I claimed final victory over Cathi’s woolly aphid

5 comments:

  1. I used glyphosate here to create the borders in what was an all lawn garden, when we moved in, and then planted straight into the dead turf. It never fails to amaze me how few gardens do no dig!

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    1. You mention in a previous comment you were at Askham Bryan in the seventies. As you were an Agric(!) you would not have heard a lecture by Dr Robinson, then director of Kinsealy Research Station doing exactly what you say - planting direct into the dead sward. (Killed with paraquat in those days before glyphosate was invented)

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  2. Direct drilling Became all the fashion around then, as you mention using paraquat.

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  3. Very interesting. It took me a while to realize that Ground Elder is what I call Bishop's Weed. I have the variegated kind. I remove all flowers, and it has not been an aggressive spreader.

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    Replies
    1. Hi Jason.
      I know in your country it's Bishop Weed and I agree the variegated form looks lovely when the flowers are removed. I never get round to removing my flower stalks with mine planted in Bolton Percy cemetery, although for the record it's never self seeded

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