The green carpetweed (Mollugo verticillata) is a common annual weed often considered invasive. It likely originated in the American tropics but has propagated across much of the world. In summer, it spreads to create a “carpet” of ground-covering foliage and is thus often considered a weedy pest in gardens.
I. Appearance and Characteristics
Mollugo verticillata, the green carpetweed (also known as Indian chickweed), is a rapidly spreading annual plant from tropical America. In eastern North America, it is a common weed growing in disturbed areas. It forms a prostate circular mat that can quickly climb over nearby plants and obstacles. The species has been reported from every state in the United States except Alaska, Hawaii, and Utah, as well as from British Columbia, Manitoba. Ontario, Quebec, New Brunswick and Nova Scotia. Although considered an invasive weed, M. verticillata is also known to be edible. Archaeological evidence has shown that M. verticillata has been in North America for about 3000 years. Sometimes also referred to as “Indian chickweed”, in China this plant is referred to as zhong leng su mi cao.
Carpetweed has narrow, whorled leaves, 3-8 at each node. At maturity the plant may lose its characteristic basal rosette formation. Leaves are approximately 1–3 cm in length and possess an obovate shape. Leaf apex may vary from rounded to acute. The plant will grow and sprawl across the soil due to its habit of prostrate growth and form mats. The flowers are usually in clusters of 2-5, blooming from July through September. Flowers are white or greenish white with tiny 5–15 mm stalks. Flowers quickly turn into fruit that is egg shaped and 1.5–4 mm in length. The dehiscent capsule opens at maturity. The seeds are 0.5 mm long and are red to rusty brown in coloration.
Carbon dating has dated seeds of M. verticillata found in Icehouse Bottom Tennessee back to 1170- 140 B.C. Other seeds found in Troyville, Louisiana were dated back to 500 A.D. It is unsure exactly when or how M. verticillata spread into temperate North America. European movements were not the cause of this migration because carbon dating reveals that the plant was in the Little Tennessee river valley 3000 years ago. Despite little apparent food value, indigenous peoples may have had uses of M. verticillata that are unclear today. Carpetweed, also referred to as “Indian chickweed”, was utilized as a potherb by the indigenous peoples of Southern Appalachia.
Carpetweed is considered to be globally secure. It is also credited as an invasive weed by USDA.gov. IUCN RedList states that the taxon has not been assessed for the IUCN Red List. Other accounts cite the weed as being native to the Continental US, Caribbean territories, Mexico and introduced to Canada. It can be found in disturbed habitats such as fields, parking lots and gardens.
II. How to Grow and Care
Green carpetweed is a low-maintenance plant that thrives in a variety of environmental conditions. It primarily requires adequate sunlight and regular watering to ensure healthy growth. A special care point for green carpetweed is to provide well-draining soil to prevent root rot. Beyond these needs, green carpetweed generally requires minimal intervention, making it suitable for individuals seeking an easy-care plant.
Sunlight
Green carpetweed flourishes in full sunlight conditions where it receives direct and abundant light for optimal growth. Despite this preference for bright environments, green carpetweed exhibits resilience to partial sun, tolerating less intense light while still maintaining health. Any significant deviation from these light conditions can lead to stunted growth or reduced vitality. Green carpetweed uniquely adapts to varied light exposures by adjusting its foliage orientation to maximize light absorption. For outdoor cultivation, selecting open areas that receive unfiltered sunlight for the majority of the day is recommended to foster green carpetweed’s robust growth.
Watering
Thriving in its native habitat’s well-drained soils, green carpetweed exhibits a preference for consistent moisture levels. This species is resilient to periodic dry spells but flourishes when the soil remains slightly moist. Watering every week supports its health and growth patterns. As an opportunistic groundcover, green carpetweed often finds its niche in outdoor settings where it can capitalize on natural rainfall, making it less demanding of supplemental watering during the growing season.
Propagation
Green carpetweed propagation predominantly occurs through sowing in Spring. Generally, it’s quite easy to propagate, and successful growth is indicated by emerging seedlings. Attention to proper soil moisture is crucial for optimal sprouting.
Transplanting
The prime time to transplant green carpetweed is in its S2-S3 growth stage, often coinciding with late spring or early summer. This ensures strong root establishment and ample growth. Choose a sunny location with well-drained soil for best results. Remember, green carpetweed appreciates care, so handle with caution during transplantation!
III. Uses and Benefits
Along with Glinus (Molluginaceae), Mollugo are edible plants that have historically been utilized as vegetables or for medicinal benefits. The family Molluginaceae has been studied for its therapeutic characteristics due to the production of triterpenes saponins and flavonoids. One study suggested that ethanolic extracts of M. verticillata could be a potential immunomodulator. The chemical makeup in members of the family Molluginaceae in general has anti-fungal and anti-inflammatory properties.