Michauxia tchihatchewii/ catherine wheel

Hi All,

I have grown Michauxia tchihatchewii/ catherine wheel  from seed this year I hear its a beautiful plant.My plant's have just been potted on into 4inch pots but unsure if to plant them out in October or leave them with extra protection in the greenhouse over winter .I live on the east coast in lincs and last year it broke all records and went down to -18..Common sense tells mt to plant them in spring.has anyone else grown these plants before and any advice please be grateful.

I grew it once, but failed to collect seeds. It is a biennial or very short lived perennial and hardy( supposedly) to about -12c. Long long time ago though so not up to date info.

thanks well think may keep them in a warm bed just in case..