Many insular plant taxa naturally consist of small populations, which are increasingly impacted today by herbivory, climate change, and competition with invasive plants. Are some insular species fated to extinction or do they still have potential to recover? To help explore this question, we studied Schiedea adamantis, a federally endangered shrub from the Hawaiian island of O‘ahu where it was originally known as a single population. This population underwent a population crash in the late 1990s, declining from >250 plants to a handful of plants before several more individuals were discovered nearby. Fortunately, plants grown from seed obtained before the bottleneck had been maintained ex situ in California. Using microsatellite markers, we confirmed that levels of genetic variation were lower in the bottlenecked population compared to the pre-bottleneck and offspring collections, but overall levels remained moderate in the wild population despite the severe reduction in size. The four remaining field individuals consisted of one plant that likely persisted through the bottleneck and its progeny. The ex situ offspring collection contained four unique alleles, indicating the value of these collections maintained offsite. Subsequently, new plants located downslope from the original population and a second genetically different population on the same island were also discovered, although numbers continue to decline. In addition to ongoing reintroduction efforts, levels of genetic variation and discovery of new individuals holds promise for in situ survival of this species, but only if its habitat can be protected from fire, increased drought, and competition from invasive species.