Once the plant set seed and the leaves go mushy, they're usually finished. I would pull them out and shake the seeds right back into the area where they were growing. Lychnis is a biennial, so to have them blooming each year, you need to sow seed (or set out plants) two years in a row. After that, they usually self sow. When you thin the seedlings, keep in mind the need to have "new" and "old" plants in the bed at all times.

Thanks! I probably missed some this year, but the mother plants that aren't mushy are huge and reblooming, so maybe I'll get some good seedlings.

I love rose campion and wherever I grow them, also include some pretty light orange poppies. The two colours together look so summery and pretty.

Oh, that's a neat idea. I have some seeds to sow in late fall for spring blooms here in my zone.

Thanks for the companion idea!