Verbena hastata L. - Blue Vervain

Verbena hastata plant

Family - Verbenaceae

Stems - To 1.6m tall, branched above, herbaceous, pubescent, often slightly scabrous, 4-angled.

Verbena hastata stemStem at a node.

Leaves - Opposite, petiolate, lanceolate to lanceolate-oblong or lanceolate-ovate, to +/-3cm broad, +15cm long, serrate to double serrate, scabrous above, pubescent below.

Verbena hastata leaves

Inflorescence - Multiple terminal spikes, with flowers dense and overlapping, indeterminate.

Verbena hastata inflorescenceSingle spike of inflorescence.

Flowers - Corolla whitish to blue-purple or rose, to 10mm long, 4mm wide at apex, tubular, salverform, 5-lobed, zygomorphic. Stamens 5, included within corolla. Calyx to 3mm long, tubular, pubescent, 5-lobed(toothed).

Verbena hastata flowerFlower close-up.

Flowering - June - October.

Habitat - Moist ground, waste ground, pastures, thickets, meadows, streambanks, roadsides, railroads.

Origin - Native to U.S.

Other info. - This plant is sometimes confused with V. urticifolia L. but the latter has flowers which are not as dense on the spikes and with corollas which are typically white. V. urticifolia also has much broader leaves than does V. hastata.
V. hastata is a common plant and can bloom when quite small if mowed or cut frequently.
Steyermark lists three forms for the species. Form hastata, pictured above, has the typical blue-purple corolla. Form rosea Cheney, has a rose-colored corolla and is rare. Form albiflora Moldenke, has a white corolla and is also rare.

Photographs taken off Shaw Ave., St. Louis, MO., 7-28-03.
 


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