Click on terms for botanical definitions.
Blue porterweed is a low-growing and sprawling evergreen shrub. Its leaves are dark green, oval– to lance-shaped with serrated margins and are oppositely arranged. Its diminutive purplish-blue flowers are borne on long spikes. Flowers open for only one day and won’t open on very cloudy days.
Blue porterweed typically flowers in the summer, but may flower year-round in South Florida. It is an excellent addition to a butterfly garden. It is the host plant of the tropical buckeye 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).
Stachytarpheta is from the Greek stachys (spike) and tarphys (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 or loamy soil
Exposure: Full sun to partial shade
Growth habit: 1-3’ tall with 2-3’ spread
Propagation: Seed, cuttings
Garden tips: Blue porterweed is drought-tolerant and does well in poor soil.
Note: The non-native Stachytarpheta cayennensis is often mistaken for the native S. jamaicensis as both have the distinctive purplish-blue flowers. S. cayennensis, however, is a Category II FLEPPC listed invasive species and should not be planted. 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.