I came across a NZ flax plant with some seed heads (mostly empty) and removed as many as I could. My own plant is still young, and the garden centres only seem to carry varieties with colourful leaves rather than the species. I’ve sown a few seeds that remained in the pods and will see how they grow. I notice these plants every time I go back to England – there was even one growing on Brighton Beach (clearly a landscape planting rather than self-sown), so they must be extremely hardy to tolerate both SA summers and English winters along with salt spray.
The Woolcraft Book states that you can get a purple-brown colour from the pods with a copper modifier, but I just stuck to the usual alum/CoT and alkaline modifier routine. The book also mentions allowing the pods to ferment for a period of time, and warning of the offensive odour. I left them soaking in plain tap water for about 5 days; the black dye came out of the pods quickly, but I’m not sure whether the 5 days added to the effect. There was no smell, but perhaps that was due to the lower temperatures, now that we’re in autumn.
The alum/CoT mordant (samples 2 & 4) transformed the yellow-brown to a more pinky-brown, whereas the alkaline modifier (samples 3 & 4) deepened the shades. I hope to eventually have more of the resource to play with and also to try processing the fibre.