Great choice Bob and welcome from me, too! I've just been doing that very thing - removing hundreds of wild violets growing under my roses (dig.. ouch!, dig.. ouch! etc etc!) Perhaps I should change my name to BleedingBobTheGardener!
A trowel in the hand is worth a thousand lost under a bush.
Raise your hand if you are here to advertise weed killers that do not work on horsetails.
Glyphosate won't work. Glyphosate actually encourages field horsetail by eliminating competing plants. Horsetails love poor drainage, low oxygen, and acidic soil. You need to improve your soil by applying lime. After AT LEAST two weeks, apply horse manure. Then some nice compost. I've tried killing them with industrial grade vinegar (20%) but, like anything applied to them, it will only kill the tops and do nothing for the roots (which can go as far down as 7 meters...or over to Japan). Also, it acidifies the soil.
Covering any parts of your garden with membrane or plastic will just make the roots really happy without the oxygen and horsetails will pop out everywhere along the sides. Don't do it. That's what the previous owner did here. You lift up the sheet of plastic and it is nothing but horsetail roots under there. They don't like shade so you can crowd some of them out with taller plants.
From March to May you must be very vigilant and pull out any female (asparagus looking) horsetails as soon as possible as they spread thousands of spores everywhere. Make sure to pull them out and place them directly in a plastic baggie to contain the spores and landfill them.
Do not till as it will make things worse. Every bit of root will regenerate into a new plant. We need to realise that they may never, ever fully go away. They take a lot of silicone from your soil so you can compost them after drying them out in order the replace the silicone.
Try to improve your drainage by sloping the land away from your property and adding some ditches for the water to flow down. Some simply say it is best to pull out what you can and then just deal with them. The roots go so far down that they don't compete too much with plants for nutrients (allegedly) and the best thing to do is encourage them to move along by improving the soil.
Very hard to do if your neighbour has them. Now that our lawn has been dug up, I've been trying to figure out what to do next. There are still tons of roots out there, but we're going to apply lime, then a layer of gravel to help drainage. Then manure, then some compost, and then turf. If anyone has any other suggestions...it would be much appreciated. Just stop with the commercial weedkiller advertisements. The stuff has been proven (by other people on these boards) not to work on horsetails at all.
I think it's been well established that neither method, not glyphosate nor continual pulling out and shading, cultivation and liming will get rid of horsetail (also known colloquially as marestail in some areas) - as you've said, " I've been trying to figure out what to do next. There are still tons of roots out there.... "
Both methods, if repeatedly applied will, in my experience, give the gardener a degree of control.
Gardening in Central Norfolk on improved gritty moraine over chalk ... free-draining.
I also read somewhere that turnips, planted thickly with seed from a farm supply shop prevent the horsetails roots from coming up again. One guy said he tried it, but it took three years.
I don't like turnips, but I might try it along the edge of the garden that is currently under the gravel to see if it helps. Maybe instead of a lawn this year, I should just do turnips? Bleh.
I know little about lawn or whether or not adding gravel to the clay will help to improve drainage.
Been battling with Mare's Tail/Horsetail for many years (over 40yrs in 2 gardens) - completely and utterly defeated, until I found following solution four years ago. As Mare's Tail invariably comes up in midst of other plants I wait until its approx. 6" long, then place a short piece of plastic drainage pipe over each frond, held in place by wire peg. Yes - the garden now looks completely absurd. Then, each day for 1 week, I stroll round the garden and spray a tiny squirt of diluted "Kurtail" into each pipe. Then wait (patiently) until the weed withers completely - this takes approx. 2 to 3 weeks when the "remains" can just be gathered up - by this time the weed-killer should have reached the whole root system. Whatever you do DON'T break the root system by digging, rotovating or pulling-out as at each break the weed regenerates multiple and enthusiastic new growth.
This has worked over the last 4 years. Started with approx. 200 pipes (honestly) - after 4 years down to about 20 per year this is manageable and almost enjoyable as I creep around the garden every May/June searching for these green devils but now prepared with a proven strategy. Kurtail needs careful and responsible handling - as do all chemicals!!! It seems to penetrate the waxy surface of the weed better than alternatives.
Worked so well that I returned to our former home to rid that garden of the infestation of Mare's Tail - as a good-will gesture to the current owners. The solution has worked there also!
Posts
But be warned, they are all bonkers on the Forkers thread, but if you like virtual tea, cake and the occasional wine then that's fine
Great choice Bob and welcome from me, too!
I've just been doing that very thing - removing hundreds of wild violets growing under my roses (dig.. ouch!, dig.. ouch! etc etc!) Perhaps I should change my name to BleedingBobTheGardener! 
Raise your hand if you are here to advertise weed killers that do not work on horsetails.
Glyphosate won't work. Glyphosate actually encourages field horsetail by eliminating competing plants. Horsetails love poor drainage, low oxygen, and acidic soil. You need to improve your soil by applying lime. After AT LEAST two weeks, apply horse manure. Then some nice compost. I've tried killing them with industrial grade vinegar (20%) but, like anything applied to them, it will only kill the tops and do nothing for the roots (which can go as far down as 7 meters...or over to Japan). Also, it acidifies the soil.
Covering any parts of your garden with membrane or plastic will just make the roots really happy without the oxygen and horsetails will pop out everywhere along the sides. Don't do it. That's what the previous owner did here. You lift up the sheet of plastic and it is nothing but horsetail roots under there. They don't like shade so you can crowd some of them out with taller plants.
From March to May you must be very vigilant and pull out any female (asparagus looking) horsetails as soon as possible as they spread thousands of spores everywhere. Make sure to pull them out and place them directly in a plastic baggie to contain the spores and landfill them.
Do not till as it will make things worse. Every bit of root will regenerate into a new plant. We need to realise that they may never, ever fully go away. They take a lot of silicone from your soil so you can compost them after drying them out in order the replace the silicone.
Try to improve your drainage by sloping the land away from your property and adding some ditches for the water to flow down. Some simply say it is best to pull out what you can and then just deal with them. The roots go so far down that they don't compete too much with plants for nutrients (allegedly) and the best thing to do is encourage them to move along by improving the soil.
Very hard to do if your neighbour has them. Now that our lawn has been dug up, I've been trying to figure out what to do next. There are still tons of roots out there, but we're going to apply lime, then a layer of gravel to help drainage. Then manure, then some compost, and then turf. If anyone has any other suggestions...it would be much appreciated. Just stop with the commercial weedkiller advertisements. The stuff has been proven (by other people on these boards) not to work on horsetails at all.
I think it's been well established that neither method, not glyphosate nor continual pulling out and shading, cultivation and liming will get rid of horsetail (also known colloquially as marestail in some areas) - as you've said, " I've been trying to figure out what to do next. There are still tons of roots out there.... "
Both methods, if repeatedly applied will, in my experience, give the gardener a degree of control.
Gardening in Central Norfolk on improved gritty moraine over chalk ... free-draining.
I also read somewhere that turnips, planted thickly with seed from a farm supply shop prevent the horsetails roots from coming up again. One guy said he tried it, but it took three years.
I don't like turnips, but I might try it along the edge of the garden that is currently under the gravel to see if it helps. Maybe instead of a lawn this year, I should just do turnips?
Bleh.
I know little about lawn or whether or not adding gravel to the clay will help to improve drainage.
Think that gives you two more options - learn to like turnips or learn to like horsetail
Gardening in Central Norfolk on improved gritty moraine over chalk ... free-draining.
Been battling with Mare's Tail/Horsetail for many years (over 40yrs in 2 gardens) - completely and utterly defeated, until I found following solution four years ago.
As Mare's Tail invariably comes up in midst of other plants I wait until its approx. 6" long, then place a short piece of plastic drainage pipe over each frond, held in place by wire peg. Yes - the garden now looks completely absurd. Then, each day for 1 week, I stroll round the garden and spray a tiny squirt of diluted "Kurtail" into each pipe. Then wait (patiently) until the weed withers completely - this takes approx. 2 to 3 weeks when the "remains" can just be gathered up - by this time the weed-killer should have reached the whole root system. Whatever you do DON'T break the root system by digging, rotovating or pulling-out as at each break the weed regenerates multiple and enthusiastic new growth.
This has worked over the last 4 years. Started with approx. 200 pipes (honestly) - after 4 years down to about 20 per year this is manageable and almost enjoyable as I creep around the garden every May/June searching for these green devils but now prepared with a proven strategy. Kurtail needs careful and responsible handling - as do all chemicals!!! It seems to penetrate the waxy surface of the weed better than alternatives.
Worked so well that I returned to our former home to rid that garden of the infestation of Mare's Tail - as a good-will gesture to the current owners. The solution has worked there also!