Verbena hastata (L.)
Plant Symbol = VEHA2
Swamp vervain Blue verbena
Swamp verbena Simpler’s joy
Ethnobotanical: Blue Vervain is used internally to treat depression, fevers, coughs, cramps, jaundice, and headaches. Externally, it is used for acne, ulcers, and cuts.
Warning: Blue Vervain can interfere with blood pressure medication and hormone therapy. Large doses will induce vomiting and diarrhea.
Landscaping: Blue vervain produces very attractive purplish-blue flowers in late summer. It can grow in degraded wetland habitats and is an excellent landscaping substitute for several invasive species, including European wand loosestrife, purple loosestrife, and purple foxglove.
Wildlife: The cardinal, swamp sparrow, field sparrow, song sparrow, and slate-colored junco eat the seeds of blue vervain. The cottontail rabbit will sometimes eat the foliage; most other mammalian herbivores avoid it due its bitter taste. The caterpillars of the verbena moth feed on the leaves and it is the larval host for the common buckeye butterfly. Long and short tongued bees collect the nectar and sometimes the pollen. Other bee pollinators include: epoline cuckoo bees, eucerine miner bees , halictid bees, and the verbena bee, a specialist pollinator. In addition the thread-waisted wasp, bee flies, thick-headed flies and golden soldier beetle are also known to all visit blue vervain.
Description and Adaptation
Blue vervain is a native, perennial wildflower that grows from 2 to 5 feet tall. Its hairy, square stems can be green or red. The toothed, lance shaped leaves progress in pairs up the stem and are about 6 inches long by 1 inch wide. Purplish-blue flowers bloom in multiple, showy, elongated panicles (flowers arranged on a stem) and are up to 5 inches long. Each bloom is about 1/4 inch across and conspicuously lobed. Blue vervain blooms in mid to late summer; approximately 1 1/2 months after blooming each bloom gives way to four oblong, reddish-brown, triangular-convex “nutlets.” Blue vervain spreads through rhizomes, horizontal roots that produce new plants.
Blue vervain prefers moist conditions and full to partial sun. It can grow in disturbed sites and is commonly found in moist meadows, thickets, and pastures, as well as riversides, marshes, ditches, and river-bottom prairies.