Carolina Cherry Laurel. Here is a link that might be useful: Prunus caroliniana

Why remove the leaves? The plants love them, but I know if you're dealing with an HOA, you may not have a choice. I had bromeliads, gingers, amaryllis, crinums and philodendrons under my oaks. I planted the philodendrons by laying them up against the oak tree trunk and covering with a pile of dirt. They eventually grew up into the tree and were gorgeous. I loved not having to rake under the tree, or even fertilize much, because of the leaves. Never "planted" a bromeliad. Just laid them on the ground and let them do their thing. The gingers only need an inch of dirt over them to grow. The giant crinum was planted quite by accident when I was given one which I tossed under the tree and forgot about. It rooted into the ground, still growing on its side, and bloomed like mad every year. The amaryllis I started as tiny bulbets given to me by a friend, so I only had to dig a tiny little hole and cover with dirt to start them. They took a few years to bloom, but they did, and multiplied like mad. There is a grass that will grow under oaks. It's called "Bitter Blue" St. Augustine, and it's not that easy to find. Mine was there when I moved in, and wherever it grew out from under the shade, it died, because I didn't irrigate the lawn. Still, it thrived under the oak. Monkey grass is also easy to plant and grow under oaks, because you can pull the clumps apart and just plant the sprigs. It fills in rapidly. Same with the green or variegated ornamental sweet potato. Just root some cuttings in water and plant them as soon as they have tiny 1/2" roots on them. Of course, you can always mulch and use containers for flowers if you want. A lot of people do that.

I've seen aspidistra (cast iron plant) used effectively under very large oaks. There are both solid green and variegated varieties. Another possibility is aucuba japonica. With its yellow variegation, it brightens a shady area. I read that this would do well among tree roots so I planted a small - but well rooted - cutting in an area filled with palm roots. What a trooper it has been! It's now about 2.5 feet high and has added some pizazz to the site. Floridata says its a slow grower that will eventually get to 8-10 ft high, but at the rate mine is growing (admittedly fighting for its share of water and nutrients), keeping it at 2-3 feet would be easy-peasy. June Here is a link that might be useful: Aspidistra

I'm afraid you can suffocate your tree if you add more than 2 or 3 inches a year of soil and etc. over the roots of your trees. Been there, done that, and I am still paying for it even after I removed most of the soil. Having said that I have a whole garden area under my oak tree including pathways. The soil should be in good shape because of all the leaves (that's if you left the leaves on the ground) that fall and decompose. I have planted all types of tropical plants and salvias under this tree. If all your trees are fairly close you may want to add a landscape design that includes, if you have it, some of your sunnier areas. This will be different from just putting circles around each tree. This may be a larger project then you may want to take on but it can be done a little at a time. The feeder roots of your oak tree are usually around 12" deep so I would stick with putting smaller starts of plants in, one gallon size or less. Stay away from the 3 gallon size. Good luck and remember if you are not happy with the way the plants look you can always change it.