If you want to add lots of yellow add some annuals via seed to naturalize, you will have reliable, abundant swaths of yellow every summer and some in spring, more than you can ever hope for with just perennials. Yellow is more common summer through fall in nature & I let nature dictate the colors since it goes with the light and look of the seasons. Some heavy blooming yellow annuals are: California poppy (early), Helenium amarum, Bidens polylepis, Lesquerella gordonii aka Gordon's bladderpod (very early). Plains coreopsis, Rudbeckia hirta and Thelesperma filifolium (Greenthread), Cowpen Daisy. Add in Lazy Daisy (white), Horsemint (purple) and annual Gaillardia and you will add some other color and lots of easy bloom that will naturalize and come back reliably each year. Some of my gaillardia bloom solid yellow, some solid red but most are red flowers with yellow borders. Two good yellow perennials: Missouri primrose, blooms early and keeps going as long as there is moisture, & Englemanni pinnatifida. If I see something nice along the roadside, I often make a mental note and come back later for seed.

You have listed what appears to be what we call "Nativars", or plants that have been selected from wild collected seed and then bred to stabilize those characteristics the person found desirable characteristics. There is some beating of the drums of disagreement about their use in the Native plant growing community. I am unsure about the purpose of your thread. Are we just to list natives that we grow or natives that we know are straight species with a trade marked name in quotes tacked on. That also happens. People will take a certain population of a plant and tack their special name on the plant. Muhlenbergia emersleyi "el Torro" is one that comes to mind.In the wild it is bullgrass so it is not much of a stretch.

Heaps of them. Most of Irisgals suggestions with iberis, linum grandiflorum,coreopsis, echium vulgare, nigella bucharica, ammi majus, godetia, cosmos, phlox drummondii, phacelia campanularis, nemophila, linaria marrocana, catanache, dianthus, nicotiana affinis, scabious, succisa, stylomecon, centaurea annua, (I went a bit mad for hardy annuals and cutting flowers this year).

Is it likely I wouldn't get flowers the first year? This showed up in various sunny spots. An argument in favor of a match is that when I compared this to the Eupatorium serotinum I have, both have reddish color in some of the stems. For people who might be curious Eupatorium serotinum is a very good bee plant for me once it flowers late in the season and I like how it looks. It's a much taller plant than the one foot the mystery plant. I think I'll leave some of them and see if they flower next year unless I hear that no flowers this year means not a match. Thanks again for your help Jay.