Verbena stricta Vent.

Hoary Vervain


CC = 2
CW = 5
MOC = 78

© DETenaglia

Family - Verbenaceae

Habit - Perennial forb.

Stems - Strongly ascending to erect, to 1.2 m, single or multiple, simple or branching, 4-angled, moderately to densely pubescent with nonglandular, somewhat curved, more or less spreading, often pustular-based hairs, usually also with moderate to dense, shorter, more appressed hairs.

Verbena_stricta_stem.jpg Stem and nodes.

© DETenaglia

Leaves - Opposite, simple, sessile to very short petiolate. Petioles to 5 mm long, winged. Blades 1-9 cm long, at least those of the largest leaves 15-50 mm wide, ovate to elliptic or nearly circular, those of the uppermost leaves sometimes only lanceolate to narrowly elliptic, rounded to more commonly angled or short-tapered to a nonclasping base, rounded to more commonly angled or short-tapered to a bluntly or sharply pointed tip, unlobed, the margins relatively coarsely and sometimes doubly toothed, both surfaces densely pubescent with longer and shorter, appressed, nonglandular, sometimes pustular-based hairs (appearing grayish), felty or roughened to the touch.

Verbena_stricta_leaf1.jpg Leaf adaxial.

© SRTurner

Verbena_stricta_leaf2.jpg Leaf abaxial.

© SRTurner

Verbena_stricta_leaf.jpg Pressed leaf.

© DETenaglia

Inflorescences - Terminal spikes, sometimes grouped into small panicles of 3 spikes, each 4-20 cm long, indeterminate, moderately dense, the upper flowers usually strongly overlapping, appearing stout when young but often relatively slender at maturity, elongating greatly with age. Bracts 2.0-2.5 mm long, slightly shorter than to slightly longer than the calyx, narrowly lanceolate.

Verbena_stricta_inflorescences.jpg Inflorescences.

© SRTurner

Verbena_stricta_inflorescence.jpg Inflorescence.

© DETenaglia

Flowers - Calyces 5-lobed, 3.5-5.0 mm long, 5-ridged, densely pubescent. Corolla 7-10 mm long, blue-purple to rose or whitish, funnelform, 5-lobed, zygomorphic, the expanded portion 7-9 mm broad. Lobes to 3 mm long, pubescent externally and internally. Stamens 4, didynamous, included, adnate at top 2/3 of corolla tube. Anthers 0.8 mm long, yellow. Style green, glabrous, 1.5 mm long. Ovary green, 1 mm long, glabrous, superior.

Verbena_stricta_flowers.jpg Flowers.

© DETenaglia

Verbena_stricta_flowers2.jpg Flowers.

© SRTurner

Fruits - Nutlets 2-3 mm long, narrowly oblong in outline, the inner surface usually pale and with dense, minute papillae, the outer surface grayish brown, with several longitudinal ridges, these with several cross-ridges above the midpoint.

Flowering - June - October.

Habitat - Glades, upland prairies, loess hill prairies, sand prairies, savannas, tops of bluffs, streambanks, pond margins, upland forest openings, pastures, fields, railroads, roadsides, open disturbed areas.

Origin - Native to the U.S.

Lookalikes - V. hastata.

Other info. - This attractive species is fairly common across Missouri. Its larger range comprises a roughly circular region encompassing several states within the central continental U.S. The plant is usually easy to recognize by its spikes of bluish flowers; however, this description also applies to V. hastata, and the two plants can appear similar in some circumstances. In comparison to that lookalike, V. stricta has somewhat larger flowers, more robust inflorescences, and leaves with very short (<5 mm) or no petioles. It also tends to grow in drier areas, though there is some overlap in habitat. The two species, and others in the genus, have been known to cross, producing plants of intermediate morphology.

V. stricta is a typical roadside weed and is quite tolerant of disturbance. However, its large size and abundant flowers make it worthy of cultivation. Different flower color forms have been named. Form stricta, shown above, has the typical blue-purple flower color; fo. albiflora Wadmond has white flowers, and fo. roseiflora Benke has rose-colored flowers. This and other species in the family Verbenaceae often have square stems, much like those of plants in the Lamiaceae. These two families are closely related. Many of the Verbenaceae also have scented foliage.

Photographs taken at the Kansas City Zoo, 6-29-00, and near Springfield, MO., 7-4-03 (DETenaglia); also at Klondike County Park, St. Charles County, MO, 6-23-2014 (SRTurner).