Known as a highly versatile plant, Wild Senna has gained significant recognition and popularity over the years as an ideal choice for restoration projects and gardens. It is an herbaceous perennial plant that grows to an average height of 6’ and is largely unbranched.
Wild Senna is a part of the legume species and is native to Eastern North America. It is commonly found in the Appalachian Mountains and Atlantic Plains, and further down in Georgia. Some of its varieties are also common throughout Maine and the Great Lakes region. The plant’s popular habitats include disturbed areas and moist, open woodlands.
The best feature of the Wild Senna plant is its stunning and vibrant yellow flowers that often also have purple-colored spots. These purple spots offer a striking contrast against the yellowness of the flowers. These beautiful colors are further accompanied by deep green and smooth, pea-like foliage that consists of numerous round and prominent leaflets. All these colors together provide a breathtaking backdrop in your garden and take it to a whole new level!
History of Wild Senna
Although the Wild Senna plant is popular in most of the eastern half of the United States, it is surprisingly endangered or threatened in the Northeast, including various regions such as Massachusetts, Vermont, and New Hampshire.
Wild Senna is a member of the pea family (Fabaceae) and is also a former member of the genus Cassia. This plant holds great significance for its medical uses and benefits. The first known medical use of the Wild Senna plant dates back to the 9th century. The Arab physicians of those times used to brew the leaves of this plant to make a cathartic tea.
Many traditional European and Arabic medicines also featured dried Wild Senna leaves and pods. These medicines were majorly used as strong laxatives in order to treat serious constipation. Many people today also use this plant for similar purposes.
Wild Senna leaves basically work as a stimulant laxative by increasing muscle contractions in the intestinal wall. By doing so, they make it easy for the waste mass to pass through the intestines. The leaves also contain a powerful laxative compound called anthraquinone that aids in the digestion process.
Wild Senna – Plant Profile
Wild Senna is a very stunning plant that produces highly attractive and eye-catching foliage. You are likely to find this plant growing in native landscaped gardens and meadow plantings. Its blooming period begins in July and ends in August, during which it produces beautiful bright yellow flowers.
Wild Senna is most notable for its stout central stem that is slightly hairy from the top and has a nice, light green color. It produces compound leaves that are evenly pinnate, and each has 5-10 pairs of leaflets. These leaflets sport a gray-green to medium-green color and grow to an average length of 2 ½ inches. Each leaflet has a pointed tip, smooth margins, and an oblong shape.
The upper base of the Wild Senna’s compound leaves contains a small, club-shaped gland. This gland serves the purpose of attracting different kinds of insects towards it by secreting nectar.
On the other hand, the Wild Senna flowers do not contain any nectaries, which makes them quite unusual. Most plants have nectaries on their flowers in order to attract pollinators, but Wild Senna has them on the leaf petioles. Interestingly, these nectaries make use of a special kind of pollen to attract different varieties of bees and insects. According to a study, bees are highly attracted to this special pollen that consists of a high protein-to-lipid ratio. This is primarily why bumblebees commonly forage on the Wild Senna plant.
This plant produces clusters of bright yellow blooms that greatly attract hummingbirds, bumblebees, and butterflies. The flowers look like cup-shaped disks, and they consist of a dark-colored bulb toward the center. Each flower measures almost 3/4” across and consists of five yellow petals, five pale yellow sepals, a pistil with white hairs, and ten stamens that have dark brown anthers.
The best time to plant Wild Senna is the spring or the early fall season for guaranteed success. Like various other legumes, initially, this plant has slow growth from the top because it sends all its energy into the root system where growth is optimal in the initial stages. This slow top growth goes on for a period of two years until the roots become fully established. After the two-year marker, the Wild Senna plant begins to grow rapidly.
Wild Senna grows best in soils that are well-drained in partly shaded or sunny locations. The plant easily grows up to a height of 7 feet in fertile and damp soil while in dry soil conditions, it only manages to attain a height of 3 feet.
Wild Senna has a plethora of uses and benefits that greatly contribute to its popularity. It serves two major purposes: ethnobotanical and landscaping.
In terms of ethnobotany, many species of the Senna plant are popular as laxatives or purgatives. The strong laxative compound present in these plants is what keeps the cattle and other herbivores from grazing on them.
Additionally, the Cherokee from the Southern Woodlands of the United States commonly consumes an infusion of the Wild Senna plant for various purposes such as fever, cramps, and heart trouble. They specifically use the root of this plant in an infusion and give it to children to combat high fever. Other people tend to use this plant as a worm remedy, to treat pneumonia, and cure fainting spells.
Secondly, Wild Senna is known for its ornamental value with the gorgeous foliage that offers a striking contrast against its clusters of bright yellow flowers. Its breathtaking appearance makes it an ideal choice for gardens and meadows, where it not only adds great beauty and aesthetics but also attracts butterflies and birds towards it.
Pest and Infestation Problems
Wild Senna doesn’t have many prominent or common diseases and pest problems. In fact, insects and pests avoid feeding on this plant because of the strong laxative compound present in its leaves. The plant is also highly drought-tolerant; however, it does grow to flop over while the seedpods are developing because of its tall height.
Types of Wild Senna Flowers
Wild Senna plant has very limited varieties or cultivars; however, each of them is very popular and is considered to be the perfect type of plant for growing in gardens by a majority of people.
Take a look at the most common types of Wild Senna flowers that you can also grow in your garden for that added beauty and splendor.
1. American Senna
This is quite a head-turning type of Wild Senna plant, primarily because of its fanning oval-shaped leaves. It produces pea-like yellow flowers that greatly attract bumblebees and provide them with pollen and nectar. The flowers of this plant go on and on for weeks during the peak blooming period, which is why the American Senna is such a show-stopper.
American Senna is native south to Tennessee and Georgia and east to Southern New
England all the way from Illinois and Wisconsin. The plant grows to an average height of 4 to 6 feet and spreads almost 5 feet wide, which gives it a very shrub-like appearance.
The blooming period of the American Senna flowers begins sometime during spring and ends in the fall season. During this period, the flowers of this plant continue to bloom for four weeks or even more, given that they are provided with the ideal growing conditions. The plant requires full sun to partially shaded areas to attain its maximum height, coupled with medium to moist loamy and clayey types of soils.
When growing American Senna, it is essential to keep in mind that one of its key growing requirements is perfectly moist soil with just the right amount of moisture in it, so it is best to stay away from dry loamy, or dry clayey types of soils. It is also best to plant it in such a place where you can easily see the seed heads and observe them developing from the inside.
American Senna’s fanning leaves are indeed very unique and attractive. However, one of the most distinguishing traits that will make it truly stand out in your garden is the way its flowers develop and grow into seedpods. After pollination, the flowers produce furry, white, tongue-like protrusions that gradually transform into ornamental seeds. These seeds greatly attract birds in the winter season, mainly because they tend to change color in the fall.
American Senna is best used as a perennial hedge, considering how it has a distinct horizontal root structure that makes it super resistant against the wind. The plant also looks great on a garden bed or even in the center of a mixed border.
2. Indian Senna
As its name implies, the Indian Senna plant comes from India, where it is popularly cultivated in the western and southern regions. It is also native to numerous other regions; it is found in great abundance in Lower Egypt, particularly in the Nubian region, as well as near Sudan, where it is cultivated on a commercial basis.
Indian Senna is a small, erect shrub that grows to an average height of 2 to 3 feet. It has a smooth, pale green stem that grows in an upright manner. The leaves of this plant sport a green-yellowish color and they grow on spread-out branches. These leaves grow about 1-2 inches in length, and they have a unique and elongated spear shape. The dorsal surface of the leaves is a yellowish-green color while the upper part is a shiny green color. This color duo perfectly complements the bright yellow flowers produced by this plant.
Indian Senna is also referred to by two other names, which are: Alexandria Senna and Egyptian Senna. These names stem from the fact that in ancient times, Alexandria in Egypt was the main trading port. Fruits and leaves of this Senna plant were commonly transported to Alexandria from numerous places, such as Sudan and Nubia. From Alexandria, they were further transported to Asia and Europe through the Mediterranean Sea.
This variety of Wild Senna has a vast number of uses and benefits. The leaves of the Indian Senna plant are often dried and then turned into powder. This powder is mixed with hot water and consumed for the purpose of treating problems like abdominal distention and constipation. The leaves of this plant are also used to treat different skin conditions and diseases by applying the leaf with vinegar to the affected area of the body.
Interestingly, Indian Senna has also proven to be very beneficial for women who are lactating, as it induces mild purgation and makes it easy for them to breastfeed their infant.
However, consumption of this plant is often linked to numerous side effects such as dehydration, excessive salivation, nausea, and increased thirst. In order to minimize or completely prevent these side effects from occurring, it is recommended that one should consume Indian Senna with a combination of either rock salt, sugar candy, or ginger powder.
3. Maryland Senna
This Senna cultivar is also known as ‘Maryland Wild Senna’ and bears great similarity to the Wild Senna plant. Both are virtually indistinguishable, except when they produce ripe seeds. The seedpods of the Maryland Senna remain tightly closed, whereas Wild Senna readily opens its pods after ripening and allows the seeds to fall out.
Maryland Senna is a flowering plant that is native to the United States. It is an herbaceous perennial wildflower that grows as tall as 6 feet. The central stem of this plant is stout, green, and slightly angular. The plant produces alternate compound leaves that grow along the entire length of its stem. The leaves are evenly pinnate, and each leaf consists of 6-12 pairs of leaflets.
These leaflets have prominent, smooth margins, and they sport an oblong-elliptical shape. The upper surface of the Maryland Senna leaves is a petty, bluish-green color while the lower surface is more of a pale green color.
This plant is best grown in moist, well-drained soils, and the soil type can range from loamy to sandy. It also prefers growing in full sun or partially shaded areas. Some common and popular habitats of this plant include riverbanks, moist prairies, limestone glades, thickets, savannas, and wooded areas.
The flowers of the Maryland Senna plant are known to be cross-pollinated by bumblebees. The plant consists of extra-floral nectaries that greatly attract nectar-feeding flies, birds, and insects. It also serves as a host plant for several butterfly caterpillar species such as Little Yellow, Sleepy Orange, Cloudless Sulphur, Tailed Orange, and Orange-Barred Sulphur butterflies, to name a few.
Maryland Senna is not just an excellent host plant, it is also a beautiful garden plant. One of its best features or characteristics is its multi-tasking abilities through which the plant not only helps beautify your garden but also feeds different species of butterfly caterpillars!
4. Northern Wild Senna
The Northern Wild Senna plant was once widespread in the entirety of New England. However, its population has drastically gone down over the years. It is commonly found growing in disturbed habitats with damp soils, forest edges, shores of lakes and rivers, meadows, floodplains, open fields, and savannas.
The blooming period of this plant begins in July and ends in August, during which it produces clusters of bright yellow flowers. Unlike flowers of other senna cultivars, the flowers of the Northern Wild Senna are less pea-like, and they are almost 20-30 mm wide. These flower clusters form a panicle toward the end of the plant stem.
Its leaves are pinnately compound, and each leaf consists of two or more discrete leaflets that grow between 2-5 cm long. The fruits of this plant grow 7 to 12 mm long by 5 to 9 mm wide since the seed pods do not readily open once fully mature. The seeds also have a square-shaped space between them, along with depressed centers.
Northern Wild Senna is considered to be a vascular plant, which means that it has a distinctive ‘circulatory system’ through which it delivers water and nutrients to all its leaves and flowers.
The Wild Senna plant is indeed a great choice for gardens, meadows , and all other similar spaces. If you are looking to add beauty and color to your garden, you must plant these beautiful flowers and have your garden buzzing and humming with bumblebees and hummingbirds!