Family: Amaranthaceae
Gomphrena vermicularis, commonly known as silverhead, is a succulent perennial plant native to coastal regions across the Americas, Africa, and the Caribbean. It is a low-growing, mat-forming herb with fleshy leaves and distinctive silvery-white flower heads. Thriving in harsh, salty environments like beaches and sand dunes, it is sometimes used in landscaping for erosion control in coastal areas and is even considered edible.
While not currently a widespread invasive weed, silverhead is naturalized on the island of O’ahu and poses a potential threat to sensitive island ecosystems like Hawaiʻi. It has a high climate match, can tolerate poor and saline soils, and has a smothering growth habit that allows it to outcompete native coastal plants. Its ability to spread both by seed and from broken stem fragments, combined with its intentional sale in the horticulture trade, increases its risk of establishing and disrupting native plant communities. For these reasons, it is considered a high-risk species and should not be planted in Hawaiʻi.
High Risk Traits:
- Suited to tropical/subtropical climates.
- Naturalized outside its native range.
- Tolerates a wide range of soil conditions, including saline soils.
- Has a climbing or smothering growth habit.
- Reproduces by seeds and vegetative fragmentation.
- Short time to reproductive maturity (1 year).
- Propagules dispersed intentionally by people and by water.
Low Risk Traits:
- Not reported as a significant agricultural or environmental weed.
- Not toxic to humans or animals.
- Lacks spines, thorns, or burrs.
- No evidence of prolific seed production or a persistent seed bank.
- Seeds not adapted for wind or external animal dispersal.
