Cultivation (growing techniques): Grass invasion
Started by: Veronica Pomfrett
Grass has invaded my rock gardenGo to latest contribution by John Humphries, 05 February 2007, 12:11. Go to bottom of this page.
Whilst my attention was elsewhere, grass invaded my rock garden (it snuck in under the fence from my neighbour's garden). I've dug up everything and used weedkiller but it keeps coming back and now I want to replant the alpines. Any suggestions for a weedkiller which will kill the grass but not my (non-grass) alpines so I can apply it when the grass comes back?
Well Veronica I can sympathise with you! My whole garden is infested with naturalised hybrid daffodils which, despite my attempts to dig them up, still manage to come up close to or in clumps of my favorite plants! My record was 80 bulbs in a foot cube of soil! Some of these bulbs are getting on for two foot down, and even if I carefully transplant my rarities and spray the daffodils they come back worse than ever! Hopefully AGS members could help us both!
Veronica, You do not mention what sort of grass you have, but I assume that it is something nasty like couch grass.
You need a two pronged attack. One to kill what is currently there, and two to prevent the re-occurrance.
You seem to have already addressed the first, the problem being the second needs to be tackled at the same time.
You mention that the grass has sneaked under the fence. I'm assuming from this that there is no physical barrier below ground level to stop any roots coming through.
You will need to dig a shallow trench along the line of the fence and insert some kind of barrier. This can be as simple as a durable polythene sheet(old compost bags part inserted inside each other to form a sleeve), or a piece of pond liner or some similar barrier. You can also buy rolls of "Grass edging" plastic about 6" high that could be used.
Once you have established your barrier, dig out as much of the grass root as you can, before planting, or better still apply a contact weedkiller(glyphosphate, roundup, etc).
Either way you must attack any regrowth promptly, couch grass will die out if promptly pulled on regrowth, and residual bits of roots will wither away when not being fed by active surface growth. A second application of weedkiller will also deal with residual roots which once severed from your neighbours growing source become a finite problem.
So the key issue is to determine how deeply the roots are invading from next door and dig a trench/insert a barrier to at least that depth.
My neighbour had a huge Kerria that insisted on coming onto the sunny side of the fence, I dealt with that by chopping back and inserting a barrier of compost bags, reinforces with old paving slabs on edge, as Kerria doesn't take any lesser barrier seriously. Problem has not re-occurred in three years.
Hope this helps. John H
Your problem is actually more difficult. Dig!
Pull off the foliage for successive years in any clumps of plants you cannot dig up and pick through the roots. Apply weed killer gel to individual leaves.
Another way of applying weedkiller amongst plants is to cut the bottom off a plastic milk carton. Place the carton neck end over the leaves of the weed/bulb like a collar used to prevent dogs scratching their ears...and spray inside the carton.