One seedling from a batch of wild collected seed of Carex trifida from New Zealand was totally different. It is only about two feet tall with a mass of four foot long whips with terminal seedheads radiating in all directions. An amazing sight.
Sow at any time, in a well-lit position, into a good, soil-based compost. Cover seeds thinly and keep moist at around 15 degrees C or 60 degrees F. Some New Zealand species can be very slow indeed and may need cooler temperatures before they will come up. Grass seedlings should be potted on and grown on singly, or in clumps for more rapid establishment of a large specimen.