Arrowroot (Maranta arundinacea) is a perennial herb found in rainforest environments. Currently, this species is grown mostly in St. Vincent in the series of Caribbean islands. This plant is commercially viable because the root starch extract is used to make foods, makeup, and glue.
I. Appearance and Characteristics
Maranta arundinacea, also known as arrowroot, maranta, West Indian arrowroot, obedience plant, Bermuda arrowroot, araru, araruta, ararao or hulankeeriya, is a large, perennial herb found in rainforest habitats of the Americas, but cultivated in tropical regions worldwide.
Maranta arundinacea is native to Mexico, Central America, the West Indies (Cuba, Hispaniola, Puerto Rico, and most of the Lesser Antilles) and South America (in Brazil, Peru, Ecuador, Colombia, Venezuela, Suriname, Guyana, and French Guiana). It is widely cultivated in many warm countries and is considered naturalized in The Bahamas, Bermuda, Cambodia, China (Guangdong, Guangxi, Hainan, Yunnan), the Cook Islands, Equatorial Guinea, Gabon, India, Indonesia, Jamaica, Japan (in the Volcano Islands), Mauritius, the Netherlands Antilles, Réunion, Samoa, Sri Lanka, Taiwan, Trinidad, Tonga, the United States (Florida), the Philippines and Vanuatu.
The Caribbean island nation of St. Vincent and the Grenadines is the world’s largest grower of arrowroot and producer of arrowroot flour. In Kerala, India, arrowroot, locally called bilathi koova, is cultivated to produce an easily digestible starch.
Arrowroot is a perennial plant growing to a height of between 0.3 m (1 ft) and 1.5 m (5 ft). Its leaves are lanceolate. The edible part of the plant is the rhizome. Twin clusters of small white flowers bloom about 90 days after planting. The plant rarely produces seeds and reproduction is typically by planting part of a rhizome with a bud. Rhizomes are ready for harvesting 10–12 months after planting as the leaves of the plant begin to wilt and die. The rhizomes are fleshy, cylindrical, and grow from 20 cm (8 in) to 45 cm (18 in) long.
The arrowroot plant probably originated in the Amazon rainforest of northwestern Brazil and neighboring countries. It grows best between temperatures of 23 °C (73 °F) and 29 °C (84 °F) with annual precipitation between 150 cm (59 in) and 200 cm (79 in). The dormant rhizomes can withstand temperatures as low as 5 °C (41 °F).
In the continental United States, arrowroot is cultivated as an outside plant only in southern Florida.
II. How to Grow and Care
Sunlight
Arrowroot thrives in partial sun conditions where it receives bright, indirect light. It can adapt to both full sun and full shade, but too much direct sunlight may scorch its leaves, while insufficient light can lead to leggy growth. Optimal growth is achieved with consistent, diffused lighting that mimics the dappled sunlight of its natural understory environment. Outdoors, arrowroot should be planted in a spot that provides protection from harsh midday rays but welcomes morning light. Indoors, a north-facing window or a room with filtered sunlight is ideal. The plant’s leaves may exhibit phototropic behavior, adjusting to the light source, which maximizes photosynthesis and contributes to its overall health.
Temperature
Arrowroot is native to tropical South America, which has an annual average temperature above 20 ℃ and plenty of rain. Therefore, it prefers a warm and moist habitat. The plant’s growth temperature is 16 to 27 ℃ and about 10 to 15 ℃ in winter. Its preferred relative humidity is 60%. Low temperatures and dry environments should be avoided.
Watering
Thriving in the understory of tropical rainforests, arrowroot has adapted to environments with high humidity and consistent moisture. This species is known for its preference for evenly moist soil, indicative of its native lush habitat. Watering should be regular, with a schedule of once every week to maintain its preferred moisture levels. As an indoor plant, arrowroot benefits greatly from being placed in rooms where humidity levels are higher, complementing its need for a moist environment.
Soil
Arrowroot prefers slightly acidic soil with an adaptable pH of 5.5-6.0. It needs air-permeable and loose culture soil that is rich in organic matter. Because of this, using sphagnum moss is recommended. Appropriate garden soil and organic matters may be added to increase the water retention of the soil. An example of culture soil composition is 1/2 sphagnum moss + 1/4 coarse sand or perlite + 1/4 garden soil.
General nutrition soil for indoor potted plants can also be purchased at garden stores. A layer of pebbles can be applied to the bottom of a perforated flowerpot to increase drainage. Soil should be changed once every two years to avoid an accumulation of water in the flowerpot.
Fertilizing
For optimal growth, arrowroot thrives with high nitrogen fertilizers to support its lush foliage. Fertilize every 4-6 weeks during the growing season, reducing to every 8 weeks in winter. A half-strength dilution is advisable to prevent root burn. Fertilization enhances the arrowroot’s vitality, promoting vigorous growth and root development. Be mindful of over-fertilization signs, like salt buildup or leaf burn. During dormancy, minimize applications to avoid waste and potential damage. Effective fertilization involves uniform application, ensuring soil is moist, and not applying directly to the foliage.
Pruning
Old, yellow, dead, and diseased leaves should be cut off promptly to prevent nutrient consumption and promote the growth of new leaves.
Propagation
Arrowroot is a perennial tropical plant that thrives in rich, well-draining soil and with adequate moisture. When propagating arrowroot, division is an effective method. This involves gently separating the rhizomes to ensure that each new section has roots and leaves. Carefully pot each division into its container, using an appropriate potting mix that simulates a tropical environment. Water the new plants regularly, but avoid water logging to prevent root rot. Consistent, indirect light aids in recovery and growth post-division.
Transplanting
For arrowroot, the perfect transplanting time is early spring to mid-spring or late fall to late winter, as seasonal temperature fluctuations promote root establishment. Choose a location with indirect light and well-drained soil for best results. Remember, patience and care go a long way when transplanting an arrowroot.
Overwintering
Arrowroot naturally thrives in warm, humid climates, without cold winters. However, it can survive indoor winter conditions if given proper care. Adequate light, strong humidity, stable room temperature, and less water are desired. Be attentive to yellowing leaves, a sign of cold stress. Its tropical heritage means winter dormancy doesn’t occur, so arrowroot stays green all year, as long as it’s appropriately looked after.
Repotting
For the arrowroot, a perennial herb, repot every 3-4 years to accommodate its moderate growth. Best done in spring, choose a slightly larger pot with drainage to prevent root rot. Post-repotting, provide bright, indirect light and maintain evenly moist soil for this non-fussy plant to thrive.
III. Uses and Benefits
- Ornamental uses
Arrowroot is primarily grown for its ornamental broad and elliptical leaves that can be either green or variegated, and its roots, which have various traditional and modern uses. The flowers are small and white, and are borne in upright clusters. As a garden plant, arrowroot can be used as ground cover, a stand-alone ornamental, and even planted in pots.
- Culinary uses
Currently, arrowroot starch is used in food preparations and confectionery, and for industrial applications such as cosmetics and glue. The residue of starch extraction has a high fibre content and can be fed to livestock.
