|Mexican Evening Primrose|
In between talking to them, I weeded the top of the steps quite thoroughly, and planted two Euphorbia characias there. The Achilleas were taking over, and tend to be on the floppy-weedy end of the spectrum anyway, so too many of them = a mess.
I also watered in all the recent plantings thoroughly. That'll be an every-other-day task for a week or two.