I have this strip in the back, 30" deep and 15' wide
>Tons of leaf litter
>Top soil seems to be amended, but a little dry
>Even saw mushrooms growing last month
>Mix of sun and shade throughout the day
>Clay soil underneath
>Colorado
I want to try Alaskan lupine, four o'clocks (which I know can survive here with watering), amaranth, and a ground cover. I have low-but-not-no-knowledge on this stuff, I mostly just know leaf litter mulch and wood chips can help retain moisture and amend the soil over time.

Any recommendations?