Initial Sketches

I tried to combine all the things you liked from the two paintings and add in all the plants, let me know if something is missing. 

First ideas

First ideas

Colors to block in shapes

Little more refined

Map of Plants and Features

1. Line of Oaks
2. Mesquite Trees
3. Prickly Pears
4. Yucca
5. Bluebonnets
6. Indian Paintbrush
7. Prickly Poppy
8. Cypress Tree
9. Cliff Face
10. River
11. Clouds

Reference Pictures-Cliff and Water

The cliffs out at Guadalupe River State Park are what I have in mind, although I need to find the right picture once we decide on lighting/colors. The cliffs have a few overhangs, stripes where the water runs off, and they look distinctly Texan to me. 

Stripes on the rocks. This is probably the section of cliff  I would use,  just  from a different angle. 

I like the colors in the water towards the bottom of this picture.

Maybe colors for the sunlit water, if we go with bright daylight.