Experimental seed addition in a small field study resulted in establishment in 33-46% of plots after three years (Brudvig et al. 2011) (seeds were sown fresh). Transplants in a field study had 88% survival after 7 years (Mottl et al. 2006), suggesting that transplanting could be a successful method of re-introduction. Self-sows and can spread by seed once established (Mottle et al. 2006).
Mature transplants added to a woodland degraded by cattle grazing in Wisconin were "well established" and had reproduced within the eight years that the plants were monitored, but the authors did not report number of years to reproduction (Ellarson and Craven 1982).
Seed output moderate; low vegetative spread (Barkely 1986, Gleason and Cronquist 1991).