It seems to me that the method you plan to use will only provide more nutrition for the grass, encouraging it to better health and vigor. Yes, building large square foot or linear type beds, lining the bottoms with old carpeting covered with black plastic is a method you should consider. In the long run it may be the easiest method, although the cedar lumber required is expensive. If this were my garden I would do the following. First, using a trencher or tiller, dig a trench around the entire perimeter of the garden. Into the trench pour borax powder (it is available in 50# bags) heavily and cover the trench. Then plan on having a four foot wide walking path around the garden which is never planted. Borax kills and this should stop the canary reed grass from encroaching on the garden. Treatment may have to be repeated about every 5 years. Then, I would cover one half of the garden with black plastic, pegging firmly and solarize that section for the summer. On the other half of the garden I would stake out my rows, create 4' wide beds and mound up new, good soil/compost on top. The paths between the planting mounds would be tilled often to knock back the grass. Then the second year I would move the mounded soil onto the solarized side, again creating mounded beds and solarize the other half of the garden through that summer. A lot work! But if you have the patience to solarize for two years you should be rid of the problem grass and be able to remove the plastic and have a normal garden. Hopefully there is a company near you making concrete block. Such companies often have 'seconds' which are not suitable for building and they will sell the blocks for a reasonable cost. If you can find some they are very useful to hold down plastic and/or to build raised beds.

When we moved to our present house last year, there were five fairly small areas of lawn. In four areas, my husband removed the top layer, which was interspersed with some kind of plastic grid material, and we then planted those areas using individual holes for the plants and bagged soil. In the fifth area, with the toughest grass, we left in the grass except to dig large holes for the antique roses and companion plants we had chosen, which were then mulched. Over time and with the addition of more plants, the grassy area grew smaller and smaller. In the end, there were about a dozen areas of tussocks of grass. We had large leftover ceramic tiles from a bathroom project which I placed over the grassy areas. The grass underneath it turned brown in about a week during the summer and I then reused the tiles for the remaining grass. As the plants grew there was very little open room for the grass to regrow. I was careful to water the plants individually and no new grass has grown. Sounds unorthodox and even I was surprised that it worked, but it has. The other four areas were mulched, although not heavily, and no new grass has grown there either. The very hot summer this year may have had something to do with that. However, I believe the grass we had was a fairly recent planting, and that also might have had something to do with our success. I do think, though, that mulching and fairly close planting did much to help the situation.

Thanks, I will try the bamboo barrier. I wanted to try to contain it because I planned on putting in a new iris bed on the other side a few feet away. I have put in several new beds and I am starting on that area now. Right now I just mow down new shoots. I usually knock down the old reeds in early spring but never got around to it this year.

It is unfortunate that misinformation continues to be repeated about glyphosate. Denmark has not banned glyphosate, nor have "many European countries". Denmark at one point thought that some of the monitoring they were doing showed that glyphosate could move into agricultural field drainage water in autumn but once they looked at their data and related it to the methodology they used, they enacted no ban whatsoever. As the Danish Environmental Protection Agency specifically stated: http://www.egeis.org/home/main/Evaluation-GlyphosateDEPA.PDF "Against this background, the Danish Environmental Protection Agency believes that no unacceptable risk of pollution of the groundwater is associated with the currently approved agricultural use of glyphosate. The Agency thus does not consider that the updated state of our knowledge provides any technical grounds for the imposition of restrictions on the autumn application of glyphosate." Used properly, glyphosate will not pollute drinking water nor will it have adverse effects on humans. Once applied, it binds tightly to soil particles and is not herbicidally active. If it is applied to hard surfaces such as sidewalks it can move offsite of course. It can also move if there is active soil erosion carrying soil off site. It is of very low toxicity, and breaks down completely into natural constituents over time. It is of equal or lower toxicity than most household products such as detergent, soaps, shampoos, cleaners etc. and far less toxic than some of the "alternatives" often discussed such as bleach, kerosene, high strength vinegars and so on. There is so much misinformation being repeated on the web that it is difficult to get reliable information. This link provides an published overview of the available literature. Regulatory Toxicology and Pharmacology Volume 31, Issue 2, April 2000, Pages 117-165 Safety Evaluation and Risk Assessment of the Herbicide Roundup and Its Active Ingredient, Glyphosate, for Humans http://cat.inist.fr/?aModele=afficheN&cpsidt=1401479