Most retaining walls are at the bottom of a hill or slope, to keep the land from sliding over desired features (driveways, houses - that sort of thing). Building a retaining wall certainly doesn't eliminate a hillside/slope unless there is also excavation - more commonly called terracing.

That is my understanding about (and use of) retaining walls versus terracing anyway.

Retaining walls used for terracing is still hillside gardening. You are going to plant something there. It's just a different appraoch to the same topic.

eal51 in western CT

And you can't have a retaining wall without a hill!

ok, ok, I'll shut up now, back to lurking