Last year we bought a callistemon splendens, and it seems to be
growing nicely (full sun, south-facing wall), but according to the
books it should have flowered in early spring - and we've seen nowt.

Does callistemon take a few years before it starts flowering? Over the
last couple of weeks it's started developing buds all over its stems,
but we don't know if they're the start of the flowers or just more
shoots.