Ruellia simplex

Britton’s wild petunia

Nonnative to FloridaFISC Category 1 Invasive

Species Overview

Native to: Central and South America

Introduced and widely popular in the landscape trade, Britton’s wild petunia (also known as Mexican petunia) has been planted across the SE US. Its attractiveness and tolerance of varying urban landscape conditions makes it a popular choice for difficult areas as it can handle and even thrive in shade, sun, wet, dry, and poor soil. Sterile cultivars have been developed; however, they all still require maintenance to prevent escape because they will still spread via creeping lateral roots.

Species Characteristics

Family: Acanthaceae

Habit: perennial herb, to 1 m tall. Stems green or purple.

Leaves: dark green, opposite, lance-shaped, about 15-30 cm long and 1-2 cm wide, veins prominent below, margins smooth or wavy.

Flowers: pedunculate, trumpet shaped, 4-8 cm in diameter, solitary or borne in clusters at the tips of the stems, usually purple, but white and pink forms exist.

Seeds: cylindrical capsules containing 4-28 seeds. Capsules have explosive dehiscence with seeds spreading long distances.

Distribution in Florida: statewide


Spreads via lateral roots and abundant readily viable seed that can germinate in light or dark conditions. The seeds produce a gel-like substance when wet that enables them to stick to surfaces when they dry. It forms dense stands in the understory of forests, crowding out native plants and altering fire and succession regimes.

Control Methods

Preventive Measures

Do not plant. If sterile varieties are planted, manage to prevent lateral spread.


Replace with native plants in business and home landscapes.


Plants must be removed completely, both above and belowground, or they will continue to resprout making mowing, tillage or weed-eating the tops off Mexican-petunia ineffective. Instead, plants can be dug up with a shovel or equipment, with the aim to remove the entire root mass.


None known.


Foliar: 2–3% glyphosate product, often resprout from creeping lateral roots. Multiple treatments may be required.

Consult your local UF IFAS Extension for further assistance with management recommendations. Additional information can be found in the following EDIS Publication:


Learn more about this species

UF IFAS Assessment of Non-Native Plants in Florida’s Natural Areas

Atlas of Florida Plants


USDA Plant Database

Invasive Species Compendium

View records and images from University of Florida Herbarium