Click on terms for botanical definitions.
Blue porterweed is a low-growing and sprawling wildflower. Found in coastal dunes, shell mounds and disturbed areas, it typically flowers in the summer, but may flower year-round in South Florida. It is an excellent addition to a butterfly garden, as it is the host plant of the Tropical buckeye (Junonia evarete) and is a nectar source for many butterfly species including the Clouded skipper (Lerema accius), Gulf fritillary (Agraulis vanillae), Red admiral (Vanessa atalanta), and Julia (Dryas iulia).
Blue porterweed’s diminutive tubular flowers are purplish-blue with a white “eye.” They are born on long, narrow spikes. Flowers open for only one day and won’t open on very cloudy days. Leaves are dark green and ovate to lanceolate with serrate margins. They are oppositely arranged. Stems are branched and angled. Seeds are inconspicuous nutlets.
The genus name Stachytarpheta is from the Greek stachys, meaning “spike,” and tarphys, meaning “thick” or “dense.”
Native range: South Florida, east Central Florida, Hillsborough and Wakulla counties
To see where natural populations of blue porterweed have been vouchered, visit florida.plantatlas.usf.edu.
Soil: Well-drained sand, clay, loamy or calcareous soils
Exposure: Full sun to minimal shade
Growth habit: 1–3’ tall with 2–3’ spread
Propagation: Seed, cuttings
Garden tips: Blue porterweed is drought tolerant, moderately salt tolerant, and does well in poor soil. Its low-growing habit makes it a nice groundcover in dry, sunny areas. It also does well in a container or in a mixed wildflower garden.
Caution: The non-native Stachytarpheta cayennensis is often mistaken for the native the native species as both have the distinctive purplish-blue flowers. S. cayennensis, however, is recognized as a Category II FLEPPC listed invasive species because it has escaped cultivation and is altering native habitat. It should not be used. S. cayennensis has a more erect habit than the native species, which has a more prostrate habit. Be sure to purchase your plants from trusted sources to ensure you are getting the native species.
Blue porterweed is often available at nurseries that specialize in native plants. Visit PlantRealFlorida.org to find a native nursery in your area.