Not sure what zone you are in, but I have had real struggles with
perennial grasses where there is no serious winter kill. They can spread and invade, especially in a community garden where everyone has to be taken into consideration, and the future of what grows there will have to be taken care of by people who didn't plant it, or removed by others. So setting future people up for a lot of labor is one of those issues.
A thick pea/bean/clover ground cover makes great mulch, improves the soil, is mowable and the beneficial insects love them. They reseed where they aren't walked on, and with careful scattered additional plantings, they can continue until winter. In mild winter areas the clovers do really well.
It's not a good idea to use burr clover where dogs and cats are, because the burrs can give them really problems when they get in their ears and noses.
An important distinction: Permaculture is not the same kind of gardening as organic gardening.
Mediterranean climate hugel trenches, fabuluous clay soil high in nutrients, self-watering containers with hugel layers, keyhole composting with low hugel raised beds, thick Back to Eden Wood chips mulch (distinguished from Bark chips), using as many native plants as possible....all drought tolerant.