Any of the native columbines (aquilegia canadensis/chrysantha/longissima) work well.

We're currently trying these in some shaded lawn space we're converting to beds: Inland sea oats (chasmanthium latifolium), golden groundsel (packera obovata), Texas betony (stachys coccinea), wild blue phlox (phlox divaricata), and mountain pea. Not much experience yet with how they perform in north central Texas, but since sourced locally, am hopeful.

I have a similar situation, Gretchen7. Finding things that grow in shade, bloom and are easy on the water bill is not easy. I love your choices, bostedo. Hope they work out. This year I decided to go wild and blue. For spring colour and evergreen leaves phlox divaricata. For fall colour: dayflower Commelina erecta plus Gregg's mistflower. Now I just need something for the dog days. Maybe wild petunia. Fingers are crossed.

If there is some open space, bergamot does well. But it gets mildew if it's crowded. Salvia greggii likes shade, as does turk's cap.

Not evergreen, but I tried sunpatiens this year and they did well in sun, but even better in shade. But any impatiens will do well in shade.

Marti8a, Which Bergamot does well for you in shade? We had no flowers with the 'Gardenview' cultivar of Monarda didyma (Red bergamot) tried in partial shade this year. Have since read that some of these can be fussy about light, but no experience to know if it could be something else. It is multiplying, so otherwise seems happy. Figured the native Monarda fistulosa (wild bergamot) may do better, so will try next season.

Afirefly, Gregg's mistflower is another good one we'll have to try. If Ruellia nudiflora is the wild petunia you're thinking of, we're reducing should you need a source; though one plant could probably produce enough volunteers to cover a typical yard in sun or shade by about 5 years :-0

Thanks for the kind offer, bostedo. =) That was the plant I was thinking of. Luckily, we have some growing already that could be divided for my shady project. But now I am wondering if we -are- lucky. I've heard they can be invasive though our conditions are tough enough that maybe that is just what I need. hahaha

Salvia regla will bloom in spring and fall. I like to place it where a slanting fall sunset ray will light the bush afire againt the shaded oaks. I do not know about hardiness issues with it in Dallas. It does alright here cold side of Austin ( 30 miles west and UP) I like American Beautyberry ( purple and whiter berries for fall color) Salvia romeriana, ajuga repens and yellow columbine bloom at the same time and make quite the bright red yellow blue convergence.

I found the following to be growing nice in the shade:
sweet potato vine, purple queen / purple jew, blue hill salvia.

Now the salvia would do better in sun but it actually did decently in the shade, too. Enough wide growth and flowering to fill in the spot. The wonderful thing about it is that it survives the North Texas winters and keeps looking green throughout winter. Come spring and summer, it is pretty drought-tolertant also.

And as for purple queen, it will die back with the cold but otherwise, fills in the shady spots pretty well and is drought-tolerant.

Chocolate Plant Pseuderanthemum do fine in the shade and self seed