In article , Tom Atkinson thomas@tho
masatkinson.wanadoo.co.uk writes
When in USA 13 years ago I was given some
Hibiscus seed- 1 year old then. I discovered
some that I hadn't sown and planted them 2 weeks ago. I notice today that 1
seed at least has germinated.
Tom Atkinson

Last year I through down some old (early 1990s) foxglove seed in my
father's garden, and this produced lots of plants. Ditto Lavatera
trimestris seed of similar vintage, but not Allium aflatunense or
Centaurea cyanus.

Poppy seed (at least some species) can germinate after much longer.


--
Stewart Robert Hinsley