Transplants in a field study had 33% survival after 7 years (Mottl et al. 2006); hyssop self-sows and can spread by seed once established (Mottl et al. 2006); however, experimental seed addition in a small field study resulted in establishment in only 5-8% of plots after three years (Brudvig et al. 2011).
Seed output 25-100/plant; high vegetative spread (Barkley 1986, Gleason and Cronquist 1991).