blue vervain

(Verbena hastata var. scabra)

Conservation Status
blue vervain
Photo by Kirk Nelson
  IUCN Red List

not listed


NNR - Unranked

SNR - Unranked


not listed

Wetland Indicator Status
  Great Plains

FACW - Facultative wetland


FACW - Facultative wetland

  Northcentral & Northeast

FACW - Facultative wetland


Blue vervain (var. scabra) is an erect, perennial forb that rises on one or two stems from an underground horizontal stem (rhizome) and fibrous roots. It is usually 16 to 60 tall, though in favorable conditions it may reach more than 7 in height. It often forms colonies.

The stems are annual, erect, stout, moderately to strongly square, and branched near the top. They are green to reddish and moderately to densely covered with spreading to appressed hairs.

The leaves are opposite, lance-shaped to oblong lance-shaped or narrowly egg-shaped, unlobed, 1½ to 8 long, and to 1¾ wide. They are about 5 times as long as wide. They are on short, to 1 long leaf stalks (petioles). The petioles are usually winged toward the top. The leaf blades are rounded, angled, or short tapered at the base, and tapered to a sharp point at the tip. They do not clasp the stem at the base. They have a prominent midvein, several lateral veins that arch toward the tip, and a network of smaller veins between the lateral veins. The lateral veins end before reaching the margin. The upper and lower surfaces are green and sometimes rough to the touch. They are sparsely to moderately covered with short, inconspicuous, loosely appressed, non-glandular hairs. The margins are coarsely toothed with sharp, forward pointing teeth. There is often a pair of small leaves rising from the leaf axils.

The inflorescence is a branched group (panicle) of 5 to many spikes at the end of the stem and branches. The spikes are erect or strongly ascending, unbranched, ¾ to 8 long, and noticeable pointed at the tip. They are short and moderately stout when young, greatly elongated and slender at maturity. The flowers are densely crowded and spirally arranged on the spike. They bloom from the bottom up and only one to a few complete rotations of the spiral are in bloom at any one time. Each blooming flower overlaps adjacent blooming flowers.

Each flower is to ¼ in diameter. There are 5 sepals, 5 petals, 4 stamens, and 1 style. The sepals are green, and are united at the base into a narrowly bell-shaped tube (calyx), then separated into 5 short teeth that are unequal in length. The calyx is 1 16to long. The modified leaves (bracts) at the base of each flower are narrowly lance-shaped, sharply pointed, and 1 16to long. They are slightly shorter than the calyx. The petals are purple to purplish-blue, rarely pink or white, and ¼ to long. They are fused at the base into a slender, funnel-shaped tube then separated into 5 spreading lobes. The lobes are ¼ to 3 16 in diameter and blunt to rounded at the tip. The flowers are not fragrant.

Each flower produces a cluster of 4 reddish-brown nutlets that are enclosed in the persistent calyx but are exposed at the tip. Each nutlet is narrowly oblong to narrowly oblong elliptic in outline and 1 32 to 1 16 long. They may be faintly ridged on the bottom and have a few faint cross ridges toward the top.




16 to 60


Flower Color


Purple to purplish-blue


Similar Species


Blue vervain (Verbena hastata var. hastata) lower, larger leaves have 1 or 2 lobes near the base.


Moist. Marshes, meadows, fields, swamps, roasdside ditches. Full sun.




July to September




Distribution Map



7, 24.









  Kingdom Plantae (green algae and land plants)  
  Subkingdom Viridiplantae (green plants)  
  Infrakingdom Streptophyta (land plants and green algae)  
  Superdivision Embryophyta (land plants)  
  Division Tracheophyta (vascular plants)  
  Subdivision Spermatophytina (seed plants)  
  Class Magnoliopsida (flowering plants)  
  Superorder Asteranae  


Lamiales (mints, plantains, olives, and allies)  


Verbenaceae (verbena)  
  Tribe Verbeneae  
  Genus Verbena (vervain)  
  Section Verbena  
  Series Candelabrae  
  Species Verbena hastata (blue vervain)  



Common Names


American blue vervain

blue verbena

blue vervain


swamp verbena

wild hyssop












The upper angle where a branch, stem, leaf stalk, or vein diverges.



The group of outer floral leaves (sepals) below the petals, occasionally forming a tube.



A pyramidal inflorescence with a main stem and branches. Flowers on the lower, longer branches mature earlier than those on the shorter, upper ones.



On plants: The stalk of a leaf blade or a compound leaf that attaches it to the stem. On ants and wasps: The constricted first one or two segments of the rear part of the body.



A horizontal, usually underground stem. It serves as a reproductive structure, producing roots below and shoots above at the nodes.



An outer floral leaf, usually green but sometimes colored, at the base of a flower.

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