Oh i can relate! It looks like you are doing a great job with what you are trying, and learning as you go, anyway.

I finally took down a tree that drove me crazy this year. It was a mimosa...the world's messiest tree. It was overhanging my perennial bed, and 4 times a year it had a variety of messy litter it would shed all over the bed. It has these cool pink pom pom puff balls, but mine was so tall that you couldn't really appreciate them on the tree (35 feet up), but you sure saw them all over the garden as they turned into mushy brown blobs everywhere. I also have a garden that is backed by a mountain laurel grove and THAT has a big norway maple behind it. So LOTS of root competition. Things do okay, but definitely don't thrive there. Anyway, good luck!

For us the lilies and day lilies do well under the trees. The iris, ajuga. Seasonal bulbs and plants: mertensia, bloodroot, Solomon's seal, crocus, lily of the valley. Later, wood betony, coral bells, columbine, sedums. We don't dig under the trees. We do light mulching. Shrubs in the shadier area include small hollies, and box. Pots of heliotrope can add color in later summer. EP

I'll second the day lilies and columbine and most of the time I get foxglove to produce nice flowers and I get a seasonal bleeding heart - grows great in spring and flowers then disappears. On the more medicinal side, both my goldenseal and sweet woodruff love it under the trees

It's my first year trying some brown mustard as an annual under the trees and they seem to be flowering very well and I want to try lady's slipper if I can get a nice damp spot under all the oaks, hickory and pine in the yard. Oh, and another one that has worked well from the bulb side has been giant Colchicum - fall flowering and looks like a huge crocus.

The only things I have luck with in the dry soil under trees are flowering weeds (wildflowers to me, LOL). No one's allowed to mow them.

Susan, funny you say that..some very pretty 'weeds' have come to that border, I keep the ones I like. I look forward to them. A very tiny five petaled magenta dianthus looking 'weed', plus a few more. They are wild flowers.

JoAnn, I don't know if you are thinking about annuals but I have a huge pine tree in front of my house. I have been planting impatiens there every year and they look beautiful all around it. Since they don't like the sun, it provides perfect shade for them, the New Guinea impatiens look really lovely. Good luck!

Giniene, thanks..I acutally have impatiens in there..they do tend to flop, I have to constantly water them..not enough moisture there for them in most parts of that border..I have lots of annuals in there though. Mostly snapdragons, petunias, some verbena,pansies, cosmos, marigolds, portulaca does well there..alyssum, vinca...I have some nicotiana and lantana...it is just very hard and dry soil..mulch helps. Thanks the New Guinea impatiens would do better you are right, I hadn't thought of them for there. JoAnn... :)

Joey, I have that dianthus weed this year, too. A gorgeous specimen is being cultivated in full sun in my perennial bed. I hope I don't regret it. I wonder what it is.

I don't find it invasive in my border. A few plants here and there, I've had it for several years now...kinda wish there were more. I have rose campion there too, forgot, they do ok there..reseed here and there..always a surprise.

It's dianthus armeria, Deptford pink. I looked it up.

Cool, thanks...now it has a name!

Some people only garden under trees. Check out the gardening in shade forum. Some of the prettiest plants grow in shade:
Trillium
Astilbe
Hosta
Fox Glove
Bleeding heart
Bugbane
Monks Hood
Iris Cristata
Coral Bells
Hepatica
Blood Root
Toad Lily -Tricyrtis
Ferns-Lots of pretty ferns
Arisaema
Veronica
Ginger
etc. Check the shade section or any nursery

One thing I have noticed about planting under Pine trees, in particular, is that slugs don't bother the hostas at all. It must be that the pine needles are detrimental to their slimy little bodies.

Depends on which trees. Maples really suck up all the nutrients and moisture but oaks, apples and such are not as shallow rooted. Lily of the valley does fine under maples and so does columbine. In areas where the shade isn't so dry, astilbes, brunnera, violets, hosta, epimediums, hellebores, heuchera and pulmonaria. Pulmonarias are my most favorite but I'm also growing rodgersia, ferns, tricytris, double bloodroot, deianthe.... Under a twisted hazel I have cyclamen hederifolia which likes it dry and the hazel sure keeps it that way.

Anyone had any luck with Merrybells (Uvularia grandiflora) in shade?

Funny you should mention that, two showed up this year on their own in the very garden I am talking about. I know my neighbor has them all over in shade at her place. Wildlife must have brought seeds or something this way. I left them this year. I dont' know much about them...but the soil there isn't very moist, so I doubt they will become a problem.