maybe not st. augustine
On second thought, the grass that's springing up again in the native section is most noticeably not sprouting in the border areas that are dedicated exclusively to St. Augustine, so maybe that's not what it is. It grew quite confidently in the cold until last week's very hard freeze. Now it is severely wilted. Whereas the St. Augustine is simply brown.
When it next comes back strong, I'll have to make a proper ID.