Sure it's a very common form of edging method.

I certainly do it. I use an edging tool widely available in garden centres. It looks like a half moon shaped tool Easily cuts through grass. You need only to cut the trench at an angle so the trench forms a V shape. To keep it neat and remove any stray grass, you need to cut it again from time to time.

Thanks Ianna. No one I know seems to use this method and many on my block use that plastic black edging. Do you happen to have pictures of your gardens with this trench-like edging or know of a website with pictures? I just want to make sure that the look of the edging is what I am wanting. May I ask you some questions?

Why did you choose this form of edging? Is it easier than other methods or just a preference for you? Is it easy to keep under control once a year or is it throughout the season that you have to continue to cut it back. How about watering the plants? Do you find that the water run off makes it hard to keep the plants hydrated? Thanks for responding to my post. I know it isn't the most interesting question, but I really would like to see how many people use this method. I thought I would be able to find it online.

Well the main reason is ease. My edging tool is one of my favorite tools.

I also use the plastic inground edging material and found that it's hard to create or to keep a straight edge. I have it around my pond. Not only did I have to dig down a trench, I had to nail it down to keep it in place and then back fill it. If you get it wrong, you'd have to it all over again. Not fun. Not to mention, it's expensive. However I do use this method because of tight space and I would like to have as much grass as possible in my backyard. A properly set edging must only have it's top part seen and the rest of it underground. I also tried the other kind which was to hammer down the edge -- it doesn't look very nice and it curls up too much. Ineffectual if you need to edge a straight line.

As for the trench form of edging, I used on the beds by the sides of my home and also for a small bed besides the deck. It was much more easier to do. It is easy to maintain and probably as little just once in a season.

For these particular beds I've not experienced problems with water run offs and that's due to many reasons. I have a garden bed with well broken and conditioned soil. I keep mostly perennials with deep penetrating roots. Water tends to disappear into the bed and not into the trench. The beds should only be set slighly higher than the grass but not that much higher. Don't do a volcano mound for example.

Below is a good link to more information on trenching.

Here is a link that might be useful: edging

Oh, perfect! Thanks for the site. I feel better now that I can try to do it correctly. I will loosen up the dirt periodically and hope that it helps with the run-off. My perennials are getting more established now but these gardens are fairly new still, relatively. We have only had some of them for a year or two. So I work on it. Thanks so much for responding!

Hmm if you have problems with run offs, can you not create a depression around the plants so water does not immediately flow out?

I have this trench edging too, around most of my perennial flower beds and around the asparagus bed. Its easier to maintain than anything else I've found. I do mine with a shovel (spade type). I just dig it out here and there when it needs it and I have the shovel in my hand.

I have tried physical edging but found that keeping the grasss edged around them was a lot more work, so I took them out. This is easier.

My beds are full of ground covers so the water doens't run off into the trench.

I can also drive the mower with the wheel in the trench.

Have you considered using an edging plant? I have Erigeron karvinskianus along the edges of the beds and it does a good job of blending the beds with the lawn. They will fill in as they get bigger. I started with 12 plants and as they spread, moved new plants to bare spots. It is not invasive and unwanted plants can easily be weeded out.The small button flowers are white and turn pink as they age - not brown - so they always look neat. You don't mention what zone you garden in but check for hardiness.They should be hardy to zone 6.

They are also called Santa Barbara Daisies.

I find the 'trench' to be the easiest to maintain. Once a year cut straight down and there you have it. We have many gardens and have many forms of edges such as pavers, rocks, plants, etc. Here;s a photo of one.

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Well, that gives me a lot of options to keep the water in the garden, rather than in the trench. Ok, so a plant as an edging and maybe deepen the area around each plant to help keep the water there. I also thought that perhaps its time to add mulch to help keep the water in the garden too. Some rocks would be a benefit too. I think I could try each of these to really make this type of edging work for me. Thanks so much for the ideas, I appreciate it so much.