|Photo: Tree Collard, credit to Perennial Tree Collards blog.|
Tree collards don't seem to bolt like other greens, rarely flowering and going to seed. The seeds also don't germinate "true", so any propagation will need to be through cuttings. Found a bit more information on how to grow & maintain tree collards from Richards Farm. I've ordered some cuttings through Bountiful Gardens (along with some Kakai pumpkins that make hull-less seeds), and look forward to trying these out.