Sue writes

"K" wrote
It's easy to grow from seed, although you will presumably get a
mixture of the pink and white forms. (I say 'presumably' because I
have so many of both I don't know whether either form comes true - but
the pink is the normal 'wild' form, and the white a variety).

I can't say if the white form is -invariably- true from seed, but so far
mine have always had white offspring. I grew the first ones several
years ago now, from seed given me by a farming friend who'd found it on
her land.

Whereas I bought a packet of white seed, and now hove about 2/3 pink,
1/3 white (except when I do selective culling). I can't remember the mix
in the first year - whether the initial plants were all white.
--
Kay