Propagation and Transplanting of an Endangered Alpine Species, Robbins’ Cinquefoil Potentilla robbinsiana (Rosaceae)

Abstract

Robbins' cinquefoil (Potentilla robbinsiana Oakes ex Rydb. [Rosaceae]) is best propagated for outplanting on high elevation restoration sites in New Hampshire by treating seeds to increase germination and by outplanting nondormant plants in mid-July. Best seed germination occurred by: 1) treating seeds with gibberelic acid (GA₃) before sowing in spring; or 2) sowing seeds outside in late fall thereby subjecting them to natural freezing and thawing during winter. Both methods produced seedlings, but pretreatment with GA₃ increased germination more than 2X to 86%. First-year survival on the alpine sites was 90% when actively growing transplants were moved from the sea-level nursery and ouplanted in mid-July, rather than 11% when shipped directly in early June from freezer storage. These successful techniques contributed to this plant, placed on the list of endangered and threatened species in 1980 and found only at 2 locations in the alpine zones of Mount Washington and Franconia Ridge, New Hampshire, being removed from the list in 2002. This out-planting technique may be useful for other high-elevation species.