Introduction to Commelina communis
Commelina communis, Commonly known as Cuban canutillo, Japanese asango, Asian chicken herb, is an annual or perennial herbaceous plant of the Commelinaceae family. This species is easily recognized by its striking blue flowers and its ability to adapt to a wide variety of environments, which has made it both an easy-to-maintain ornamental plant and a herb considered a weed in some countries.
Originally from East Asia, its distribution range Today, it spreads across various temperate and subtropical regions around the world. Its hardiness, beauty, and versatility of use have led to its successful introduction to Europe, America, and other areas, where it is cultivated or appears spontaneously.
Morphological description of Commelina communis
Commelina communis It is a plant that can grow erect or decumbent, reaching up to 90cm lengthThe stems are fleshy, branched and have the particularity of being able to root in the nodes that come into contact with the substrate, facilitating their propagation and its ability to colonize large spaces.
the leaves are alternate, lanceolate to ovate, with a smooth and shiny surface, they measure between 5 and 15 cm long, and have a basal sheath that partially envelops the stem. The edges of the leaves are usually smooth, although some varieties show some waviness or roughness. Their appearance is reminiscent of a dwarf bamboo due to its elongated shape and staggered arrangement on the stem.
The inflorescence of Commelina communis is characteristic: it appears at the tips of the stems or in the upper leaf axils and consists of several flowers surrounded by a spathiform bract (like a "quesadilla"), folded longitudinally and with partially fused edges. Generally, only one flower opens outward, while the others remain hidden in buds.
The flowers have three petals: two upper ones, wide and of an intense blue color, and a third lower one, much smaller, of white color. They measure around 1,5 centimeters in diameter and have an ephemeral appearance, as they only remain open for one day: they open at the beginning of the morning and begin to close around noon.
In the center of the flower are six yellow stamens, of which four are usually staminodes (infertile), while the other two produce viable pollen. The plant is easily self-pollinated, although the presence of pollinating insects can increase pollen dispersal and genetic variability.
- Estate: They develop fleshy roots, mainly at the nodes, allowing the colonization of the substrate and the formation of new plants by fragmentation.
- Fruits: produces globose capsules, usually with 2 or 3 seeds grayish to black in color, smooth surface and slightly compressed.
- Lifecycle: Although in many areas it behaves as an annual plant, it can be perennial in favorable climates.
Taxonomy and common names
Commelina communis It belongs to the Commelinaceae family. Its botanical classification is:
- Kingdom: Plant
- Division: Magnoliophyta
- Class: liliopsid
- Subclass: Commelinidae
- Order: Commelinales
- Family: commelinaceae
- Gender: Commelina
- Species: communis
The name "Commelina" was given in honor of three botanist brothers named Commelin, two of whom were scientifically distinguished, while the third was less well-known. Hence, the two large petals represent the famous brothers, and the small white petal represents the lesser-known one.
Other common names depending on the region: yazhicao in China, tsuyukusa in Japan ("grass dew"), "chicken grass", "Japanese asango", among others.
Geographic distribution and habitat
Commelina communis It is native to East Asia, specifically China, Japan, Korea, and neighboring regions. Thanks to its great adaptability and spread, it has become naturalized and even invasive in large areas of Europe, North America, South America, and other parts of the world.
- In America: It is found in most states of the United States (except Alaska and Hawaii), Mexico (in Baja California Sur, Chiapas, Colima, Distrito Federal, Durango, Guanajuato, Guerrero, Hidalgo, Jalisco, Morelos, Nayarit, Nuevo León, Oaxaca, Querétaro, Sinaloa, Tabasco, Veracruz, Yucatán), and from the southern US to Argentina, including countries such as Brazil, Paraguay and Uruguay.
- In Europe: It has been introduced and is common in the center and southeast of the continent.
- In Asia: Native and very common in China, Japan, Korea and other humid and temperate regions.
- Other regions: Also documented in Africa as a naturalized or invasive species.
Prefers the Wetland habitats, cultivated land, roadsides, wastelands, gardens, crop edges and scrublands. It can be found from sea level to altitudes of 1500 meters, with a clear preference for sandy or light soils, as long as they have good drainage and humidity.
Commelina communis It tolerates both direct sunlight and partial shade, although its best blooms are obtained in well-lit spaces. It tolerates moderate temperatures, but cannot withstand intense and prolonged frosts.
Flowering season, pollination and biological cycle
The flowering of Commelina communis It occurs primarily between spring and summer, although in temperate climates it can last from early summer until well into autumn. The duration of each flower is ephemeral, but the plant produces flowers continuously for several weeks or months.
Pollination can be self pollination (the flower itself fertilizes itself) or Cross pollination Through insects, especially bees, which are attracted by the intense blue color of the petals and the striking arrangement of the stamens. This dual strategy ensures the species' reproduction and persistence in variable environments.
The life cycle varies with the climate: in cold areas, it is annual, germinating in spring and completing the cycle in autumn; in climates without severe frosts, it can become perpetual through rooting of stems and rhizomes.
Ecological impact and control
Although appreciated as an ornamental plant and useful in natural systems, Commelina communis is considered a undergrowth in certain crops. Its presence is notable in fields of rice, sugarcane, coffee, citrus, banana and some ornamental plants. It is not normally a weed of high concern, but its low susceptibility to herbicides such as glyphosate and its rapid spread can make it difficult to control, especially in conservation tillage and no-till systems.
- Resistant to standard doses of glyphosate; only high doses and targeted applications can control it.
- Moderate sensitivity to herbicides such as 2,4-D.
- Its abundant presence in nitrogen-fertilized soils and in humid conditions favors its proliferation.
The mechanical control (manual uprooting, clearing or tilling) and integrated weed management in crops where it is problematic.
Traditional and current uses
Commelina communis has ornamental, medicinal, culinary and dyeing applications:
- Ornamental: Used to cover floors, pots, and as a ground cover in gardens. Its blue flowers are highly decorative.
- Medicinal: In traditional Chinese medicine it is valued as a febrifuge, anti-inflammatory, antipyretic and diuretic. It is used to treat sore throat, tonsillitis, and as an aid to reduce fever. Its mucilage has been used in eye drops to treat eye irritations.
- In India and other regions of Asia: It is consumed as a vegetable and fodder in rural areas.
- Dyeing: The juice of its flowers was used in Japan and China to dye fabrics with a characteristic blue tone, highly valued in traditional art and crafts.
- Culinary: The fleshy roots are considered edible in some cultures.
Pharmacological studies have identified active compounds, such as p-hydroxycinnamic acid (antibacterial) and D-mannitol (antitussive effect). Its use is mainly in traditional medicine and does not replace conventional medical treatments.
Commelina communis cultivation care
Commelina communis It's a low-maintenance plant, perfect for rustic gardens, roadsides, pots, or areas where rapid coverage and prolonged flowering are desired. However, certain care can optimize its development and flowering.
- Substratum: It prefers light soils, with a mixture of sand and peat (approximately two-thirds sand), rich in organic matter, and well-drained. It tolerates moderately fertile soils, but not compacted or waterlogged.
- Irrigation: It requires constant, but not excessive, moisture. The substrate should be kept moist, but avoiding water stagnation. In dry climates, increase watering frequency.
- Light: It tolerates full sun and partial shade. Direct sunlight increases the intensity of the flower color.
- Temperature: It doesn't tolerate severe or sustained frost, but it does survive slight drops in temperature. Ideal for temperate climates.
- Multiplication: It can be easily propagated by seed or stem cuttings. The stems root upon contact with moist substrate, so partially burying a segment is enough to obtain a new plant.
- Plagues and diseases: Highly resistant to pests and pathogens. It can grow in harsh environments and tolerates some soil contamination.
- Pruning: Regular pruning stimulates branching and flower production.
Differences with similar species and frequent confusions
Commelina communis can be confused mainly with other species of the genus, such as commelina erecta y Commelina diffusaThe key differences lie in the number and color of the petals (Commelina communis has two blue petals and one white, while others may display three blue petals), and in the shape of the bract or spathe that surrounds the flowers.
In the Pampas region and other warm areas, similar species can be found that share medicinal and ornamental properties, but it is important to verify floral morphology for correct identification.
Curiosities and symbolism
In Japan, the name tsuyukusa (grass dew) refers to both the fragility and ephemeral beauty of the flower and the humility and transience of life, being a recurring artistic theme in poetry and painting. bright blue color Its petals have traditionally been used in oriental arts and calligraphy.
Due to its ease of self-pollination and rapid colonization, Commelina communis is a symbol of adaptability and resilience In nature.
Main active compounds and biological properties
At the chemical level, in addition to the compounds mentioned (p-hydroxycinnamic acid and D-mannitol), the plant contains anthocyanins responsible for the blue color of the petals, saponins, alkaloids, tannins and other components with biological activity.
Its medicinal uses include:
- External use for eye care, as an anti-inflammatory and soothing agent for conjunctivitis and irritations.
- Internal use: decoctions to treat fever, inflammation, throat and urinary tract conditions.
- Diuretic and antiherpetic effects in folk medicine of various cultures.
Ecological importance and as an ornamental resource
In addition to its use in traditional medicine, Commelina communis It fulfills relevant ecological functions:
- It promotes soil coverage, preventing erosion in disturbed environments.
- Attracts pollinators, especially bees, due to its vibrant blue coloration.
- It serves as a refuge and food for auxiliary fauna in the ecosystems where it develops.
In gardening, its easy propagation and hardiness make it suitable for low-maintenance gardens, naturalized gardens, and spaces where striking, ground-covering blue blooms are desired. It is also used in large containers, borders, and as a filler in mixed beds.
As an ornamental plant, it is ideal for those who want to add color and life to their garden without major complications.
Although simple in appearance, Commelina communis It is a fascinating species for its history, usefulness, and ability to adapt to numerous environments. Its brilliant blue flowers and ecological, ornamental, and medicinal value captivate it, deserving a prominent place in both gardens and botanical and ethnobotanical studies.