The message
from "Chris Stewart" contains these words:

Hi,
I have grown Phormium Tenax from seed - collected locally from an old
garden in Aberdeen. The largest of my plants (all pot grown) would be 4 - 5
ft high with a spread of 3 - 4 ft - it's in a largish pot - 20" or so. It
would be 3 -4 years old now. Has anyone any idea when it might / could
flower? Should I try giving it a higher potash feed this spring?

Last year in our new garden on Arran, I planted several, all from GC
pots and smaller than yours..I was very surprised when one of the
variegated ones grew a flower spike in its first summer of liberty.
Although the flowers themselves are not specially beautiful, the flower
spikes are very striking and so are the long twisty seed pods. On large
old plants on the island you see many flower spikes, reaching 10 ft +.

How long did it take you to grow them to 5ft from seed? I planted some
seeds (purple phormium) in autumn which germinated a couple of weeks
ago.

Janet.