Buffalo grass stays at about 6". It is a warm season grass however, which means it doesn't get green until late May.

Here is a link that might be useful: Buffalo Grass

consider a landscape plan that includes both tall and short plants. tall plants around the rear side of garden pond make great for asesthetics if its planned/landscaped nicely, you wont have to mow.

and buffalo grass is probably what you are looking for a sturdy short ground cover.

there are also no-mow fescue mixes that grow slowly - they do need to be mowed occaisionally but only about once or twice a year.

You could also simply not mow a strip around the pond. At first you'll just have tall lawn grasses, but afterwards a successsion of plants will move in (some nasty invasives, but some surprising and welcome natives). Even a narrow unmowed strip will allow lots of critters to get to the pond. Many small animals will not venture out without cover.

We have a 5000 gal pond with a 6 x 5 biofilter pond and stream. We planted Astilbe, hostas, and daylilies around the pond, bio-pond and stream, so that when the backyard must be mowed, the mower is more than 3/4 feet from pond. How about ajuga (sp?) sorry, and pachasandra and don't forget white clover further out. I could send you a picture through your e-mail but cannot post on the forum, don't belong to those "facilities"
Marian