Reference

Yarrow / Achillea

Achillea 'Coronation Gold'
From Agua Fria Nursery fall 2020

Achillea lewisii (also tomentosa) 'King Edward' - took these out
From Bluestone Perennials fall 2019

Photos 

Expectations:
Do not overwater. These want dry conditions.

Experiences:
I put a single 'Coronation Gold' yarrow in the hot dry strip by the driveway for a pop of mustard yellow in springs dn then the dried soft brown flowerheads all summer after bloom.

'Coronation Gold' in May 2022 and 2023

The ground cover 'King Edward' were nice at the very front of the kitchen courtyard, but I took these out. They are tiny plants, so best seen close up, but they really are wee things.

It's a dwarf yarrow that actually forms a ground cover mat, very different than the usual yarrow. It has pale yellow flowers held above fuzzy olive green foliage. Cute enough in flower.

They did okay, and would have spread to make a mat, but I didn't need any more small plants or groundcovers in this spot. And the pale yellow flowers were an off shade to the brighter yellow buckwheat blooming at the same time.