thread In whihc case,
mortaring between them may be a good idea, to prevent the grass growing between them.
Again, you could do this with drymix, rather than worrying about proper mortar, but it depends whether you are going to dig them into the ground so they're flush, or whether they're going to stick up like a little wall. If the latter, it'd be worth mortaring, I expect.

I should point out that I'm useless at this sort of thing, I just draw it.
permalink no, flush, that's the ticket
I'm just going to buy some bricks and see what happens.