Common name: Blue porterweed, Blue snake weed, Brazilian tea, Jamaican vervain, Joee, Bastard vervain, Light-blue snakeweed, Gervao, Verbena cimarrona, Rooter comb, Jamaica snakeweed, Snake weed
Blue porterweed plants are beautiful, shrubby, spreading plants that were once considered as weeds, but are now grown as ornamental plants in home gardens. These plants grow to height of 1-1.5 meters with a well-branched stem, before the stems stars drooping and growing horizontally along the ground.
The stem has a squarish cross-section, and becomes woody towards the base of the plant. A single plant can spread about a meter wide, producing beautiful purple, blue or mauve flowers that stand high above the level of the leaves, on long, thick spikes. Only 5-6 flowers open on a spike at at time, the older flowers towards the base falling away before the new ones open.
Blue porterweed plants have bluish-green, small leaves that are about 10-12 cms long with finely toothed margins. They are oppositely arranged, and roughly oval in shape. Individual flowers are tubular, about 1 cm in diameter with 5 petals that are fused towards the center.
These flowers contain nectar that attracts bees, insects and butterflies, that help pollinate them. Once the flowers fall off, the spikes hold tiny seeds inside small oblong fruits, that are released only when the spikes fall on the ground and decompose. Seed dispersal is also done by animals that eat Blue porterweed plants as fodder.
These sturdy little plants needs full sunlight, but can survive with very little water and fertilization. Hence Blue porterweed plants are found on roadsides, hillsides, open areas, disturbed soil etc. where the soil is unlikely to have a high amount of nutrients.
There are other closely relates species like Stachytarpheta cayennensis or dark blue snakeweed, Stachytarpheta australis or white snakeweed and Stachytarpheta mutabilis or pink snakeweed. The plants and leaves look reasonably similar in all these species, whereas the flowers come in different colors, as the name suggests.
Though Blue porterweed plants are considered noxious weeds in many parts of the world, it has many medicinal uses in local herbal medicine. The leaves of this plant is used to make tea, which is very good for stomach ailments and indigestion.
The plant is used to treat malaria, syphillis, gonorrhea, dysentery, diabetes, hypertension, headaches, liver ailments and ear aches. The leaves are used to treat burns, wounds and fractures.
Propagation is through seeds and stem cuttings, the nodes rooting easily when placed in water.