I can't think of anything that would work as an edging against something short like ajuga. Usually ajuga is the border!

If you keep an eye on the ajuga during May/June you should be able to keep it under control. Unlike a lot of other groundcovers ajuga only sends out its runners during the early summer and then spends the rest of the year in place, and I don't think I've ever had it spread by seed around here. If you keep a few inches clear between the lawn and the ajuga it should be ok.

Have you tried solomon seal for your rooty shade? I don't know about the native ones but the others are pretty indestructible. Epimediums as well.

I do have lots of tree roots and I don't find it easy to grow a lot of things. I've tried woodland plants, natives, like woodland phlox and tiarella. They petered out too

===>>> if that is true.. then whats the point of asking what to pair it with ... sounds like you ought to spread it around .. and go with the winner you already have ... else all you might be doing.. is adding to your list of failures ...

im sorry.. that sounds a lot crankier than intended.. please dont take offense ...

maybe a pic will help up brainstorm for you ...

ken

@katob - I’m wondering if ajuga spreads by above the ground runners, or do the root systems spread as well? I can see the runners starting already and I’ve started cutting off those that are going in the wrong direction. I just wanted to understand if that was going to do the trick.

I also have had some successes. Epimedium have been a god send. I have a lot of those and they are indestructible and very little bothers them. Rabbits don’t even eat them. [g]. I’ve also put Solomon’s Seal in places that have worked pretty well, but over this past winter the stands I had are about 2/3rds smaller than they were for some reason.

Those plants do a good job in the mid height that I need, along with ferns, and some hostas, [although the rabbits have been chewing those up a lot this year.], but I wanted something shorter for the front of borders. I’ve tried thyme in some places, that works okay. I've tried creeping Veronica, which doesn't really spread at all. I think it prefers sandier soil. Phlox subulata likes my garden, but I just don't want that to be everywhere.

I like ajuga. Like the color, the size, the flowers. I just hate it growing in a lawn and taking over, so I just want to make sure I don’t manage to do that to myself. You always think you are going to stay on top of something, like watching it in May/June, but there’s always that year, when due to life interrupting your gardening, that you drop the ball and off it goes.

@ Ken - No offense taken. :-) I guess you can’t have your cake and eat it too. I have competing priorities I guess. I started out gardening with the priority of having as low a maintenance garden as I could and avoided plants that were invasive or spread too much, for the most part. But now that I’ve had years of trying to grow under all the trees around here, I haven’t filled in the borders as much as I want to, because expected success didn’t alway materialize and I’d be starting over again with some new idea. Now I have to keep mulching heavily and/or weeding more than we’d like.

So maybe it’s not a competing priority, it’s just two sides of the coin. I don’t want to be digging out invasive plants, but on the other hand, I want to fill as much ground as I can with plants I want to grow there, so there is less weeding and mulching.

I think I have that in the yard. It's been in the same location for years. Maybe I need to divide it and use it other places. Good idea, thanks.

I was out in the garden today and remembered I have two other plants that have done well in some areas and not others. Lamium and Viola labradorica. Really like both of those too. The lamium petered out in three different places, but it's growing well in another. Where I get more sun. I love the Viola. The color is iridescent when it is in bloom. And that does start to fill in in areas where I've started it. It reseeds a lot. Nice dark foliage too and unobtrusive, the foliage is so small.