I collected and sowed fresh astrantia (masterwort) seeds from my garden late last summer, and left them out overwinter to stratify. I have had a number of the seeds germinate and now have a nice collection of small seedlings, the largest of which have 2 true leaves fully emerged so far. I've potted them on into modules and kept them in an unheated greenhouse.
I've found plenty of information online about how to encourage germination, but not much information at all on what sort of growth rate to expect from the seedlings. What sort of size will they get to in their first year, and how quickly? How likely are they to flower in the first year (I've seen one seed supplier suggesting they will flower the summer after sowing)?
I did see another seed supplier suggest that they should be planted out to a cooler area, '7 - 10 oC is ideal' apparently. Would they actually grow more quickly/happily in cooler conditions now that they've got started?
I sowed them as a bit of experiment so I wasn't expecting results in a hurry, but if they're going to get to a reasonable size this year then I will plant them out in a pot with a hosta, as apparently they are good at discouraging slugs.
I garden in the UK (West Midlands). I think the seedlings will be mostly Astrantia major, but there may be some Astrantia maxima too.