Family: Fabaceae
Lupinus perennis (commonly known as sundial lupine, blue lupine, or perennial lupine) is a long-lived herbaceous perennial native to eastern North America. This legume produces attractive spikes of blue to purple flowers in spring and early summer and grows naturally in dry, sandy, or well-drained soils, often in open woods, prairies, and roadsides. Like other lupines, it can fix atmospheric nitrogen, enriching the soil for other plants. The species is an important host for the larvae of several native butterflies, including the endangered Karner blue (Plebejus melissa samuelis), making it ecologically significant in its native range.
Although Lupinus perennis is not known to be invasive and has not naturalized in Hawaii, its cultivation should be approached with awareness of local growing conditions. The plant prefers cooler climates and well-drained, acidic soils, which may limit its ability to establish in tropical environments. While it provides food and habitat for many native insects and wildlife species, caution is advised where livestock are present—mature plants can be toxic to domestic sheep and horses if consumed in quantity. Despite this, L. perennis remains an ecologically valuable species and is generally considered low risk for cultivation in Hawaii.
High Risk Traits:
- Toxic to livestock (sheep, horses)
- Naturalized outside native range (e.g., Europe)
- History of human-mediated introductions
- Congeneric species are invasive
- Hybridizes with other lupine species
- Reproduces vegetatively via rhizomes
- Forms persistent soil seed bank (>3 years)
- Benefits from fire and disturbance
- Seeds dispersed ballistically, by rodents, and through intentional cultivation
Low Risk Traits:
- Limited to temperate climates (not tropical/subtropical)
- Not classified as any type of weed
- Lacks spines, thorns, or burrs
- Palatable to deer and other wildlife
- Does not form dense thickets
- Requires specific well-drained acidic soils
- Low seed production (<1000 seeds/m²)
- Limited seed dispersal (ballistic, no wind/water adaptation)
- Controllable with herbicides
- Native habitat reproductive failure (conservation concern)
