Family: Plantaginaceae
Antirrhinum majus (snapdragon) is a flowering plant native to the Mediterranean region, widely cultivated around the world as an ornamental. It is a short-lived perennial or annual that grows upright to about 1 meter tall, with lance-shaped leaves and showy, tubular flowers that come in a range of bright colors including pink, red, yellow, white, and purple. The flowers, which open in response to pollinators such as bees, resemble a dragon’s mouth—hence the common name “snapdragon.” It thrives in full sun and well-drained soils and is a favorite in gardens, borders, and floral arrangements.
Although Antirrhinum majus is not known to be naturalized in Hawaiʻi, it has become naturalized in other parts of the world, including Australia and North America. The species has traits—such as prolific seed production and tolerance of a range of growing conditions—that could allow it to escape cultivation and spread in the Hawaiian Islands. However, what impacts, if any, this would have on Hawaiʻi’s ecosystems are unclear. For now, snapdragon remains primarily a cultivated ornamental in the islands, but gardeners should take care to prevent accidental spread beyond managed landscapes.
High Risk Traits:
- Broad climate suitability (but not tropical)
- Widely naturalized
- Considered weedy
- Related Antirrhinum species have become invasive
- Possibly unpalatable to animals
- Tolerates many soil types
- Reaches maturity in under 1 year
- Prolific seed production
- Small seeds spread by wind and possibly other vectors
Low Risk Traits:
- Grows in temperate and Mediterranean climates
- Despite designation as weedy, no evidence of negative or detrimental impacts have been explicitly demonstrated
- May require full sun
- Ornamental flowers
- Self-incompatible (although certain cultivars reported to be self-compatible)
- Herbicides may provide effective control
