Despite intensive expert botanical scrutiny over many years no tall native rushes have been recorded from the ephemeral turf communities of L. Heron and the Ashburton Lakes. There is now one occurrence of J. edgariae (c. 6 square metres) at an ephemeral tarn south of Lake Heron. NZPCN shows one record from Arrowsmith Station in 1910 but I don't know how accurately that's located.
The question is whether this one population of J. edgariae should be treated as a weed in this instance? What is the expert opinion?