Suppression of the Ornamental Invasive Mexican Petunia (Ruellia simplex) by Native Species

Mexican petunia (Ruellia simplex) is a commonly planted herbaceous ornamental known for densely invading floodplain forests in the southeastern United States. While the use of herbicides is a typical management approach, revegetation strategies are needed not only to restore the native plant community, but also to limit reinvasion. We identified four native species appropriate for floodplain revegetation in Florida, US: bushy bluestem (Andropogon glomeratus), common rush (Juncus effusus), redtop panicgrass (Coleataenia longifolia sp. longifolia), and pinebarren goldenrod (Solidago fistulosa). In a controlled greenhouse container study, we investigated competition between Mexican petunia and native species compositions grown from seeds under varying hydrologic conditions and seeding densities. Results showed that number of Mexican petunia individuals and biomass decreased when seeded together with either pinebarren goldenrod or a mix of four native species (bushy bluestem, common rush, redtop panicgrass, and pinebarren goldenrod). Pinebarren goldenrod and bushy bluestem had a short establishment period (2–4 weeks), similar to Mexican petunia (2–5 weeks). Data from this container study suggests that revegetation with these native species could effectively compete with and suppress Mexican petunia in field conditions.