Blue Vervain


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Blue vervain, or American vervain, is a hardy and drought-tolerant plant native to North America. It is a traditionally important plant, widely distributed in almost every state in the USA and a few provinces in Canada. Moist prairies and damp thickets are its main habitats. It is a type of perennial herbaceous plant falling under the Verbenaceae family. It is used as an herb by many for colds, fevers, and headaches.

Mostly upright but sometimes slightly inclined, the wildflower plant usually grows as tall as five feet (1.5 meters). It can easily thrive on wet or moist soils under any light conditions.

Quick Growing Guide

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Botanical Name: Verbena hastata

Also Called: Simpler’s joy, Swamp verbena, Swamp vervain

En français: Verveine bleue



Water: Water lightly


Hardiness Zones:

The edges of the large, simple leaves are doubly-serrated, which arise straight from a square-shaped stout stem. The blue-colored flowers are densely arranged at or near the tip of the stems and branches. The flowers usually bloom in summer and, in most cases, appear purple, if not blue.

In addition to its above-mentioned names, the plant has some more alternate names such as Simpler’s joy, Swamp verbena, Swamp vervain, etc.

Where to Plant

In nature, it can be found in meadows, thickets, pastures, riversides, marshes, ditches, river-bottom prairies, and swamps. As a result, this plant can be used in moist areas such as ponds, bogs, and water and rain gardens. People use this plant as a landscaping substitute for other less preferred species because of its blue and purple coloured flowers.

Blue Vervain’s Characteristics

The plant is characterized by a thin but strongly built hairy greenish stem.

In some cases, they may also appear dark red or burgundy-colored. Numerous branches arise from nodes above the center of the plant, on top of which attractive flowers develop. The whole plant looks like a spear when observed from bottom to top, so maybe because of this, the botanists named it Verbena hastata, where hastata means “spear-shaped” in Latin.

The flowers are pencil-like with spikes directed upwards like candlesticks. Each spike has a ring of florets, among which the ones at the bottom bloom and mature more than those developed at the upper portion. 

Flowers mostly bloom in the Months of June, July, August, and September.

The leaves are oppositely arranged and develop all over the stem, almost extending from the part just below the flowers to the bottom of the herb. They are generally 3 to 6 inches long, 1 to 3 inches wide, and lanceolate shaped. 

Likewise, its fruits are generally brownish nut-like structures, consisting of four reddish-brown triangular nutlets. The calyx is persistent and encloses the fruits.

Cultivation Methods

Blue vervain is generally cultivated through its seeds and plant cuttings. The late summer or the early fall is a perfect time for nutlets collection. Then, the collected nutlets should be spread over a clean surface and dried for several days so that the seeds get enough time to ripen.

Subsequently, the nutlets should be crushed in order to obtain the seeds. The seeds need pretreatment for at least three months before sowing. After stratification, the seeds can be sown in a proper mixture of commercial plug and sand. Those sown seeds require great care, proper lighting, and suitable air temperature conditions until germination. 

Once they germinate and get established, they can flourish by self-seeding in the fall.

Similarly, another effective method of its cultivation is cutting. For that, a long stem, generally 3 to 4 inches, is taken, and all its leaves are removed. After that, it must be fixed in a place with suitable conditions. In around 3 to 4 weeks, roots are well-developed in that sample, and it becomes ready for transplantation.

However, people usually prefer the cultivation of blue vervain via seeds rather than propagation by cutting.

Food Source for Organisms

Blue vervain is a very useful herb that comes in handy for humans and animals for various purposes. Similarly, blue vervain is essential for various life forms in the prairie areas of America and Canada. Different species of birds, like swamp sparrow, song sparrow, field sparrow, etc., visit it to eat its seeds.

The larva of the common buckeye butterfly and the caterpillar of the verbena moth survive and develop by feeding on its leaves. Bees are often seen flying around their flowers as it is a very good source of nectar. They collect pollen as well.

However, herbivorous mammals dislike it as it has a bitter taste.

Medicinal Uses and Its Side Effects

Speaking of its advantages to mankind, blue vervain has great medicinal value. People have been using this plants roots, leaves or flowers to cure diseases and medical conditions such as jaundice, coughs, fever, headaches, depression, menstrual obstruction, etc. It can be used to make Vervain Tea.

In addition, they use it for curing acne, cuts, and ulcers.

Like almost every other good thing, this plant also has some disadvantages. It might not be better for a person to use it when he/ she takes medicine for a disorder in blood pressure. Also, people with iron deficiency, breastfeeding, and pregnant woman should avoid taking vervain-rich products. Diarrhea and vomiting can be caused when taken in large doses.

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