That's a tough question. Here is a link to a PDF file, citing seed trials showing that the germination rates of M. capillaris range up to only 20%, but it varies significantly between fresh seed and dried seed. Fresh seed worked best with 12 weeks of cold moist stratification, while dried seed did better with warm moist stratification. Cleaned (hulled) seed worked better than uncleaned.

It's a fall flowering and fruiting plant, which does self-sow modestly, so fresh seed, which receives the cold moist stratification of a winter, probably has the best chance of germination. For that reason, if I had fresh seed, I'd winter sow it, very lightly covered with medium, in a cold frame or some other protective outdoor container. Keep it moist.