Considering your climate, I'd be looking at the smallest of the picea glauca cultivars and mugo pines. Slow-growing spreading junipers may work too, if you can find very young specimens. These should be able to handle the cold weather and a bit of shade. Anything will outgrow a small space given enough time to grow, so don't plan on keeping them there for 20 years. Is there some reason mulching the conifers is not an option?

Any concern/experience with animals hiding under the hollow artificial boulder?

Any concern/experience with animals hiding under

==>>> youre asking us.. youre the one who came up with this idea.. lol ..

i wonder how it will alter the soil under and near itself.. perhaps making a micor soil climate ....

can you at least give us a link to a version of this rock.. is it solid or hollow ...

is your snow cover consistent and all winter long???

i dont understand why you would put a strip of lawn between the rock and the plants ...

ken

Artificial boulders are pretty common items, for example for covering and hiding utilities, as I already said in my OP, but here is a link https://www.google.ca/search?q=artificial+boulders&rls=com.microsoft:en-CA:IE-Address&source=lnms&sa=X&ved=0ahUKEwiOtdyEte7UAhWl7YMKHW4ZBeQQ_AUICSgA&biw=1043&bih=510&dpr=1.25

Planting around such a boulder is also quite commonly done: make a planting strip around the boulder (in my case for planting miniature conifers, see title of this thread), and there will be lawn grass around that planting strip. Hence the issues that I have identified in my OP: ingress of grass in the planting strip, etc., etc.

There is nothing to lol about if you read my OP carefully, it is quite clear and detailed (and don't misread planting strip as grass strip and things like that)

And yes, I am also asking about any actual experiences of people using such artificial boulders, for example lifting the boulder to access the utility for maintenance purposes and possibly seeing small animals using the artificial boulder as a shelter.

I have an artificial boulder covering the equipment of a defunct wellhead. I've never found any animal nesting within it; I guess I wouldn't care much if I did, though - our area is rural. From any kind of distance (i.e. when you are not right up upon it), it looks real. Color is important - try to get it as close to any natural stone that might be nearby.

For real or not, my biggest fear is rodents sheltering inside the artificial boulder, it would be a palace for them with food grown right outside of it. I could partially bury the artificial boulder and extend the perimeter downwards with a root barrier ... not sure.

Ah yes a good point; the boulder itself could be a draw and then they get the plants as a bargain thrown in. However, lots of vertebrate pests don't eat woody plants - e.g. opossum, mice, skunks). There may be various things that you can do to discourage rodents, see if Google can tell you anything. You could also try to affix hardware cloth as a 'cover' on the down side, and excavate the site as needed for aesthetic placement. I bet that hardware cloth gorilla-glued to the bottom will keep out any rodent.

The best looking edging option IMO is flagstone pieces placed low enough that the mower can run right over them. Here is what I have done in my own yard:

Concrete edgers are cheaper and easier to fit, but don't look as nice.

Yeah, I use concrete edgers but with an irregular top surface to make it look nicer. I get the most formal look with the edgers going all around the garden bed although of course deviating from a perfect circle. A less formal look can be had with the edgers only as part of the perimeter. My best looking has a cut root flare as part of the perimeter, the cut root flare also serves as a stand for a pot for annuals in the warm season.

I will certainly use such design elements (and more, e.g. small rockeries in the planting strip) around the boulder, but one vital consideration is that those design elements have to be in proportion with the boulder (i.e. those design elements have to be small for a 1 cubic yard boulder) hence miniature conifers and hence the edgers can't be too wide either or the entire aesthetics won't work. I am positive that in a practical sense, the edgers can't protect the miniature conifers from the mower or the string trimmer, i.e. I will have to literally manicure at least 1' of lawn around the whole thing even with the edgers in place.

I think I have a 50-50 chance to make the whole thing look good, and that is if I can overcome my fear of rodents inside the artificial boulder, LOL

Edit: I don't have any rodents in my front and backyard BTW and want to keep it that way :-)

In Colorado tons of conifers grow on and around natural rocks even going up some rocky mountains.

A rock may provide shelter for something....maybe some bunnies will dig a hole in the shady part.

Right up nect to a rock you might get some reflected sun and extra heat, your home lis probably larger and has a similar effect.

Fake rocks, it probably matters what they are made out of. If someone gave me a neat real rock I'd think about trimming around it and my kids wanting to climb it, shoot paintballs at it, that type of thing.