I had a ton of questions that I was going to put into a comment, but made the following assumptions:
- You have a formal landscape, possibly mulched with stone or river rock
- You want to plant something that requires trimming (this is based on your note that fescues aren't trimmable)
- You'd prefer an evergreen over a deciduous shrub, but would be open to deciduous if necessary.
One good choice (assuming a location NOT in the US Deep South) would be a Yew (Taxus x media 'Densiformis'). This is one of the shortest yews, maturing to about 4 feet but wanting to get 6-8 feet wide. The issue you'd have with a Yew is that it would prefer being kept larger than 18" (I had good luck keeping a grouping at 30" x 36"). As they mature, their lower trunks get rather thick. making it tough to keep them small. Note also that all parts of the shrub are poisonous to humans and pets.
You could also try a globe arbor vitae (Thuja occidentalis 'Woodwardii'), but that matures to 4-10 feet x 8-12 feet. That's a heck of a lot of trimming over time. Note that this shrub is NOT appropriate for an area where there are deer - arbs are deer-snacks.
The Missouri Botanical Garden has an excellent Plant Finder (http://www.missouribotanicalgarden.org/plantfinder/plantfindersearch.aspx). When I entered these parameters...
ZONE - 5
Moisture Requirements - Dry
HEIGHT - 1 to 3 feet
SPREAD - 1 to 3 feet
...it found no plants, even though it has a large database. When I changed the water requirement to Dry-Medium, it found 13 plants, several of which that I question (Diervilla? Trimmable, but can sucker), common ninebark (they do NOT like to be trimmed, and it ruins their form. The common ninebark can get quite large - I know, I used to own one). If you absolutely must trim the hedge, your best bet may be barberry.