On Jun 11, 11:25*am, Elmo dcdraftwo...@Use-Author-Supplied-
Address.invalid wrote:
…I could plant cover (it's chaparral out here in California),
I guess, but I like the grassy slope.

From your first post I take it you haven't gone to the bother of
maintaining the grassy slope until now, so why not take this as an
opportunity to save yourself some backbreaking labor and do Mother
Nature some good?

Talk with your local agriculture extension (or some place similar)
about creating a plan for gradually converting the slope from non-
native, water-slurping grass to something native, low-growing, low-
maintenance, and visually more interesting? It might not have to be
chapparal—there are plenty of Cali-native low-maintenance vegetation
possibilities.

And by developing a multi-year implementation you spread the cost out.