Honestly? I'm more concerned for your pine trees' health than for anything you're trying to grow beneath them.

Here is a link that might be useful: Why you should never

Two problems are that most conifers (and broadleaf evergreens with conical, low-branching growth habits, like hollies) look better branching to the ground (too late now) and that digging among the roots and adding compost etc. may have a detrimental effect on the roots. Since you have already been at it awhile and pleased with your efforts, just watch the trees for signs of deterioration (yellowing of foliage, reduced annual growth...) and proceed as planned.

My experience - and only that backed up with absolutely nothing scientific... for several decades, my yard has had some successful garden areas planted under arborist limbed old Spruce - several times the age of yours. The spruce are fine, the underplantings are fine, and the soil with years of needle fall is loose and fine. The light conditions vary during the day, but plants including hostas, ferns, astilbe, dicentra, dianthus, some can't bear to compost pieces of Stella d'Oro, daffodils, squill, forget-me-nots, and muscari all seem to thrive.

I don't fertilize, mulch or add anything beyond a compost topdress periodically; I'm a hand weeder so I don't dig around dinging roots, etc. and everything gets watered when it rains.

Thank you for the comments and suggestions. I was pretty bummed to hear the information on the possible state of the tree!!! I won't cut any more!! So far the trees still look healthy but I will definitely keep my eye on them. Unfortunately, what's done is done and I can't change that I limbed them up. Thanks for the suggestions on the gardening under them. I would like to salvage what I have and appreciate the adivice of experience. Too bad I wasn't aware of the forum two years ago!!

If they are really pine trees, as opposed to some generic evergreen, they will lose their lower branches anyway as they grow up. So it's hard to take that as a serious problem. However, competition from the trees is a different matter. If everything is growing satisfactorily, that's fine. However, many times the trees take all the water and nutrients.

With pines specifically the spent, fallen needles are a nuisance around small plants.

I garden under white pines that still have most of their lower limbs. It can be a bit dry under there but lots of things grow under them. I leave all the fallen needles as mulch and let them break down where they fall, other than those on the paths which get raked up and dumped on the adjoining planted areas. I've never noticed any problems with the needles and small plants. The plants may get a bit smothered for a while but they always pop up again come spring. Pine needles don't mat down like big leaves so they don't really smother anything underneath them when they fall.

They get all over the tops of them. As with other gardening situations, it depends on what particular kinds of plants you are trying to grow and how you want them to look. Different plants - and people - have different tolerances.

We have Norway pines in our back yard that are at least 30 feet all. Wild vines had grown in them years ago and killed off the bottom branches 10 up so we had those brances removed. I put in a raised bed garden under the trees and everything is doing great. I planted hydrangea, hosta, ferns and ground cover.