Family: Fabaceae

Origin, Description & Uses
Lupinus succulentus (arroyo lupine) is native to western North America, with a range extending from California into Mexico (including Baja California). It is an annual wildflower in the legume family that typically grows in seasonal wetlands, grasslands, and open slopes. The plant produces soft, succulent stems and palmate leaves, along with showy spikes of blue to purple pea-like flowers. Like other lupines, it is nitrogen-fixing, helping improve soil fertility. Arroyo lupine is valued in native plant gardens, habitat restoration projects, erosion control, and as a nectar source for pollinators such as bees and butterflies.

Risks & Threats
Lupinus succulentus is not currently known to be naturalized in the Hawaiian Islands and is generally considered low risk. However, it has traits that can allow it to establish in disturbed habitats, including prolific seed production and the ability to persist in seed banks under favorable conditions. In some regions outside its native range, lupines can spread locally in open or disturbed sites, so monitoring is prudent if introduced. Like many lupines, it also contains alkaloids that can be toxic to livestock if consumed in quantity, though this is primarily a concern in agricultural settings. Overall, while its invasive potential appears limited for Hawaiʻi, continued evaluation is recommended to ensure it does not become problematic under local conditions.

High Risk Traits:

• Can grow in >5 hardiness zones demonstrating environmental versatility
  
• Can grow in subtropical conditions (possibly only at higher elevations)
  
• Possibly naturalized outside native range in Arizona
  
• Disturbance-adapted, and labelled “weedy” on one website
  
• Other Lupinus species have become invasive weeds
  
• Potentially toxic to animals If consumed in large quantities
  
• Could be toxic to humans if consumed (unlikely scenario)
  
• Tolerates many soil types
  
• Self-compatible
  
• Able to reach maturity in <1 year (annual herb)
  
• Seeds dispersed passively by dehiscence and intentionally by people
  
• Small seeds could possibly be accidentally dispersed
  
• May form a persistent seed bank

Low Risk Traits:

• Despite possible naturalization, no reports of negative impacts documented
  
• Mediterranean to temperate climate species (may only become established at higher elevations in the tropics)
  
• Unarmed (no spines, thorns or burrs)
  
• Ornamental
  
• Beneficial to bees and other pollinators
  
• Not reported to spread vegetatively
  
• Herbicides provide effective control of Lupinus species
  
• Effectively controlled by mowing, grazing, cultivating