Stachytarpheta cayennensis (syn. S. urticifolia) - Blue porterweed

About fifty species of Stachytarpheta are native to warm climates in Asia, and North and South America. They are relatively small herbs and shrubs. Several species have showy flower spikes and are cultivated in gardens around the world. The blue porterweed is native to tropical America but is naturalized in warm areas around the world, including south Florida. Three to four foot tall stems are topped with slender spikes of dark blue flowers. These flowers attract butterflies and hummingbirds to the garden. Plants have been used for medicinal uses where native.

As a perennial, this porterweed is at its northern limit in Jacksonville. Plants die when winter low temperatures reach the mid-20's. Volunteer seedlings may appear the following spring. In warmer climates, this plant may spread aggressively by seed.