Pacific Northwest Gardening: Low groundcover for sunny slope, 1 by enith

enith wrote:
Hello everybody, this is my first post here and I need your help choosing a groundcover for a troublesome spot along my driveway in zone 7b (east of Woodinville).
As you can see on the picture I have a 4x60 foot long strip of soil on both sides of my rather steep driveway. It has typical PNW soil (clay, rocks), but I've been amending it with good amounts of compost for last few seasons. It is very dry and hot during the summer, I would say at least 10 hours of full sun and close proximity of asphalt driveway that radiates the heat baking everything around. As soon as I started amending the soil I started having huge problems with weeds coming from nearby fields. I need a suggestion for a short (no more than a foot, but preferably shorter than that), drought and heat tolerant groundcover that would effectively smother the weeds, stop or at least limit soil erosion and help retain some moisture for larger shrubs growing there right now. Those on the picture I removed as they struggled badly throughout the summer.
Thanks so much for your help.