Why has my healthy patch of Dianella tasmanica never flowered?
Stefan says: Dianella tasmanica, the Tasmanian flax lily is a rough, tough-looking perennial with toothed-leaves that always remind me of one of the more aggressive varieties of yuccas, or perhaps a saw sedge. Like most Tasmanian plants in Britain, it’s hardy in milder areas but not reliably so everywhere. It certainly should flower, producing sprays of small, rich blue flowers and then, small bluish berries.
What is odd about yours is that it appears to be fairly congested, and normally plants under this sort of stress flower readily. I can only assume yours is actually doing too well, is in too rich a soil and needs some gentle starving. This would mean moving it, so I suggest an alternative, which is to deny it any fertiliser rich in nitrogen and instead give regular applications in summer of potash-rich tomato feed.