Mexican Petunia

Ruellia simplex

Family: AcanthaceaeOrigin: Mexico, Central America, and South AmericaZones: 8-11

Invasive wild type: see the invasive-status note below
FISC Category I
Spreads by seed and rhizome

Pet & Human Safety

People: No hazard foundPets: Not on the ASPCA lists as we read them

Hazardous parts

Not yet checked.

Preparation

Not applicable: this is an ornamental flowering plant, not a food crop, and no human-toxicity source was found for it in the sources checked.

Hazard type

Not yet checked.

Hazard route

Not applicable: no sourced human-toxicity finding.

How complete this information is

The safety information on this page is partial. Where a source covers a point, it is shown; where none does, the page says so.

Toxic to pets

No ASPCA entry found.

ASPCA has not evaluated this species under any of the common names checked. That absence is a separate question from its invasive status above: a plant can be non-toxic to pets and still be an invasive-species problem for the landscape it's planted into.

PlotAndPetal cannot tell you whether a plant you found can be eaten. Only someone who can see the plant can identify it.

Look-alike warning

Could be mistaken for True Petunia (an unrelated garden-flower genus, family Solanaceae), which has its own ASPCA 'Petunia' entry listed Non-Toxic. To tell them apart: Different families entirely: this plant (sold as 'Mexican petunia' or 'Mexican bluebell,' Ruellia simplex) is in Acanthaceae; true Petunia is in Solanaceae.. Do not apply ASPCA's Petunia verdict to this plant: no ASPCA entry exists for Ruellia simplex under any name checked.

Poison control

If someone has collapsed, cannot be woken, is having a seizure or has trouble breathing, call 911 now. For any other possible poisoning, call Poison Help: 1-800-222-1222.

Emergency number source: U.S. federal law (47 U.S.C. § 251(e)(3)), read 2026-10-07.

Naturalist Lore

Historical Background & Breeding Lore

The history of this plant and its name, and how it was bred, where we have them.

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Care

Hardiness zones: USDA Zones 8-11
Water needs: Tolerates both wet and dry conditions once established (UF/IFAS Assessment Plant Directory); not drought-sensitive.
Mature size: Grows to about 3 ft (1 m) tall, spreading by both seed and rhizomes: the spreading habit is the same trait that makes it invasive.

Soil & Drainage

Pruning & Flush Rhythm

Feeding Schedule

How to prepare the soil, when and what to feed, and how and when to prune where that applies.

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