My experience gardening under a big evergreen tree is a 15-year nightmare; I almost wish I'd never started. Mind you it's not a pine but a Chamaecyparis. But even so, I suspect some elements are common - having to water constantly in summer, which is probably not good for the tree; the soil level creeping upward as each year's natural mulch is deposited and burying plants as well as landscape materials, the extreme dryness creating good habitat for pests such as weevils and cutworms which reproduce and feed ecstatically, and the fact that you can't dig enough to plant big plants but when you plant them small they never grow because they can't seem to extract enough nutrients (and maybe water) from the acidic soil. Big trees are lovely to have in many ways, but they are essentially thugs, and they don't respect the rights of people, buildings, or other plants. After all these years of re-landscaping about every three years to try to accommodate the tree, I've settled on hardscaping that I can easily keep clear of debris, and containers for planting. I do have two small raised beds, with very limited success (they get infiltrated by tree roots within 2 years). If I had a bigger yard and could garden elsewhere, I'd just give up and let the tree have its base clear. (I haven't considered removal because the tree belongs to a neighbour in my case, but due to our increasingly windy climate and the fact that the tree leans lovingly toward my tiny house, the neighbour has actually agreed to remove it this year). Having said all that, there are plants that might really thrive under a pine - cyclamen? - but for me, the lush shade garden I keep working towards remains elusive and if you can get close it's at the cost of serious labour. Even my ferns, and I've tried plenty, either don't thrive or eventually get smothered by the debris.

as a hosta gardener ... here are my thoughts under old trees .. just a list.. dont take it as editorial ... never till... dig only holes needed [the least amount of root cutting] ... and plant in what you dug out ... native soil.. and near bare root the plants ... cut roots.. reply by making more.. more aggressive ... feeder roots and invade planting holes.. and can chole out the plants you want ... always broadcast water.. never water just the plant.. else where do you think the tree will put all those new feeder roots ... same logic with ferts ... lawnsprinklers.. will NEVER water deep enough to moisten soil under such.. unless you have a specific zone for such;.. and run it for hours on end.. and dig holes.. to find out if and when you have water to at least 3 inches deep.. and then you water to maintain said moisture at that depth ... presuming that is where the roots of the plant you are putting there are ... a little surface moisture will not help a plant get 'established' i would have used round up to kill the grass.. rather than shaving off the first 2 or 3 inches of roots ... see above as to why .. new feeder roots ... well.. thats what i can think of off the top of my head ... you can grow things there ... but figuring out.. how to keep a transplant watered.. until it can compete.. is how you are going to win ... many things can handle drought.. but dont forget.. its the planting.. the time to get 'established' .. that dictates how successful you are ... you might have to water the grasses.. every week especially during the heat of summer.. in the year of planting... and maybe next year.. in drought .. and THEN.. they will become rather bulletproof ... the usual rule is.. insert finger.. and find out when they need water.. rather than relying on a schedule ... or an automated system ... good luck ken

If coreopsis is blooming under the tree, it isn't completely shaded. You might try a low growing evergreen shrub, such as one of the hollies, or even ornamental grasses such as Penesetum alopecurides "Hameln" or "Little Bunny." The grasses will die on top, but the dried tops look lovely all winter with their fuzzy flowerheads and tan foliage. They reshoot in the spring.

Not sure where you might have read it but pine needles do NOT poison the soil!! Pine needles (pine straw) are a very common garden mulch in many areas!! Nor do they make the soil any more acidic than it would normally be - both of these are garden myths. The reason many plants do not thrive under large conifers like pines (or even larger deciduous trees) is usually a combination of dry shade - a tricky gardening situation at best - and root competition. Look for spreading groundcover type plants that will tolerate or thrive in these conditions - fernleaf dicentra, epmediums, bigroot geranium, just to name a couple. Start out with small plants and give them some extra TLC (water and even some ferts) until established.