|Photo by Eleanor Dietrich|
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, gulf fritillary, red admiral and julia.
Stachytarpheta is from the Greek stachys (spike) and tarphys (thick or dense).
Hardiness: Central and South Florida (Zones 9–11)
Soil: Well-drained sand, clay or loamy soil
Exposure: Full sun to partial shade
Growth habit: 1–3 feet tall with a 2-3+ foot spread
Garden tips: Blue porterweed is easily propagated by cuttings and will also self-seed. It also drought-tolerant and does well in poor soil.
Note: The non-native Stachytarpheta cayennensis is often mistaken for the native Stachytarpheta 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. The native species is often available at nurseries that specialize in native plants.Visit PlantRealFlorida.org to find a native nursery in your area.
To see where blue porterweed occurs naturally, visit florida.plantatlas.usf.edu/Plant.aspx?id=703.