caladiums would add some annual color. Hostas and ferns would do good i would think. Astilbe could add some nice color too.

Native plants will do better if you won't be around to water in a drought. Native ferns should do. They just go dormant during the heat and drought and unless the drought is extremely prolonged will recover when it rains. For spring interest you might try some of the ephemeral wildflowers. Violets, bloodroot, tradescantia all bloom early spring and go dormant in the summer. The little bulbs called "rain lilies" (sorry I don't remember the scientific name) pop up and bloom midsummer after a rain. Hostas and Astilbe are both lovely but both need a lot of water midsummer.

I agree that native plants have the best chance of surviving our hot summers if your woodland is not irrigated, and I assume it is not. As far as what will survive there beneath the trees, that will depend on the type of soil and on what kind of shade there is.

We have a mostly dry woodland in southcentral OK. Some of the native plants that grow beneath the tall trees in our mixed woodland (many kinds of oaks, several kinds of hickories, pecans, elms, and hackberries), include shorter trees like persimmon, redbud, possumhaw hollies, wild cherries, roughleaf dogwood, rusty blackhaw virburnum, Mexican plum, and chittamwood (which eventually can get big, but it takes forever). Beneath the understory trees, there are lots of different kinds of groundcover type plants, including Indian currant/coralberry (spreads by creeping and will take over as it tolerates very dry conditions), poison ivy (unfortunately), Virginia creeper, some native sedges, several kinds of native grasses, of which inland oats seems the most shade-tolerant, native ferns like ebony spleenwort, native violets that bloom in February and March, peppervine, blodroot, a lovely deciduous shrub called American Beautyberry, a vine called Carolina snailseed, native dewberries on the edges of the woodland where they get morning sun/afternoon shade, native blackberries in open clearings in the woods or on the southern edges of the woodland, greenbrier everywhere (unfotunately) and in scattered locations near the creek banks we have early spring ephemerals like Jack-in-the-Pulpit and Mayapple. The bloodroot also does well in pastures on the edges of the woodlands. Sometimes sumacs pop up on the edges of the woodlands or in sunny clearings that develop after a large, old tree dies. We have some native asters in one spot, and buttonbush trees and brushy bluestem in a partial clearing that is shady most of the day but sunny at mid-day. Other native plants include phlox in early spring, grape vines of several different kinds running all over the place, smooth ruellia on a pond bank, ironweed and goldenrod on the edges of the woodland, alum root, rattan vine, spiderwort, plantain and rain lily. The native rain lily we have here grows on the edges where the woodland meets the meadow and is Cooperia Drummondii.

We probably have more native sedges than actual grasses within the woodland itself, and I don't know the names of them all but they are very shade tolearant.

Our soil is red clay down deep with about 10-12" of woodland soil that has created itself atop the clay. The humusy, rich woodland soil developed over the decades as leaves, wood, etc. fell to the forest floor and decomposed. We average 39" of rain a year, but have a wide range of annual rainfall from 18-20" in the driest years to 78" in our wettest year (2015) ever, but tend to be drier most years. A wet year with 40-50" is considered an incredibly wonderful year. The understory plants come and go from year to year depending on the weather conditions and rainfall. We don't see all of them every year.

Wow, that's a lot of information! You guys are ridiculously knowledgeable about this! Color me uber impressed lol!

The area has a ton of roots all through it, doesn't look like red clay at least no on top. It's surrounded by big trees so sun gets in but there's a lot of shade. Very dry it seems like, not much of anything there that's not brown. There is a creek with water running through it pretty close by (10 yards approx). The main tree looks really healthy, though.

It needs to be something that's pretty cheap to buy, can plant without any equipment (except maybe a small handheld gardening trowel), comes back each year without any upkeep (we only make it there a few times a year) and obviously look as good as possible given the restrictions.

It'd be nice to have several different kinds so that there's always something whichever part of the year we go. So a plant that completely takes over and won't let anything else grow might not be the best (unless it stays there most of the year and looks good).

With all that said, which of those native plants would you suggest?

My favorites are the american beautyberry, purple aster, bloodroot, and phlox. Anything purple especially! caladiums look good, too, but I worry they wouldn't survive very long.

What kind of aster would you recommend? There are some really pretty ones, but I assume some would survive better?

I love the idea of dogwood(!), as well as the Mexican plum. I am going to have to check on the native rain lily (didn't know we had a native rain lily!), as well as Jack-in-the-Pulpit. What about Yarrow or Milkweed? Though not native plants, my husband moved some white iris to the edge of our forested land and they are thriving. If purple is your color, that would be common enough to try on a budget.