Methownet BB

I planted a bunch of drought-tolerant, low-nutrient plants (salvia, yarrow, etc) directly in the ground in early May. Oh the stones! Full sun. They are on a drip line. I didn't amend the soil because they are poor soil plants

They absolutely suck. They have barely grown, look shocked, etc. We have fiddled with the water but no real change

Ideas

Were they small starts you purchased? Or dug up small? Sometimes these plants don't like transplanting. We have alot of yarrow that comes up naturally. I would think the Salvia would have done well.
Maybe overwatering?
There is also a product called Comeback Forumula that the Twisp Feedstore had. By Bushdoctor. Works great on faltering plants but don't know how it would work on these drought tolarant plants. Low nutrient doesn't mean no nutrients. Can't hurt to give them some kind of food. IMO. But not in the heat of the day.
I don't know much. But good luck.

Try spray them with a mixture of hydrogen peroxide & water- look it up on you tube they have videos that help resolve plants that are struggling...Teresa

Derby Canyon is a native plant nursery in Peshastin that I get some native plant starts from (drought-tolerant). They might be a good resource to consult. They mostly discourage use of soil amendments for native plants. I know from my experience that yarrow grows well from seed and doesn’t like a lot of watering. Good luck!