Origin
Nasturtium amphibium, also known as the amphibious watercress, is a member of the Brassicaceae family and is native to Eurasia, Africa, and North America. It can be found growing in wetlands, streams, and marshes across these regions.
Common Names
The common names for Nasturtium amphibium include amphibious watercress, watercress, and swamp cress. In some regions, it is also referred to as marsh watercress, brooklime, and creeping yellow cress.
Uses
The leaves and stems of Nasturtium amphibium are edible and have a peppery taste similar to that of the common garden watercress. They can be consumed raw in salads or used in soups, stews, and other dishes. Nasturtium amphibium was traditionally used in herbal medicine to treat a wide range of ailments, including scurvy, headaches, and stomach problems.
Aside from its medicinal and culinary uses, Nasturtium amphibium plays an important ecological role in wetland ecosystems. It helps stabilize soil, filter water, and provides a habitat for a variety of aquatic and terrestrial species.
General Appearance
Nasturtium amphibium is a perennial herb that can grow up to 60 cm in height. It has branched, creeping stems that can float on water and form dense mats. The leaves are simple, ovate to oblong in shape, and are arranged alternately along the stem. They are dark green in color and have a smooth texture. The flowers of Nasturtium amphibium are small and white or pale yellow in color. They are arranged in clusters at the end of the stems. The fruit is a cylindrical pod that contains numerous small seeds.
Light Requirements
Nasturtium amphibium requires a significant amount of sunlight for optimal growth and development. A minimum of six hours of direct sunlight is recommended. The plant may still grow in areas with partial shade, but the leaves will not be as lush or vibrant as those grown in full sun.
Temperature Requirements
The ideal temperature range that fosters growth in Nasturtium amphibium is between 60°F to 75°F (16°C to 24°C). The plant can survive lower temperatures down to 40°F (4°C) but any colder than that will damage or kill the plant. High temperatures above 85°F (29°C) will cause the plant to wilt, and growth will slow down.
Soil Requirements
Nasturtium amphibium grows best in soil that is nutrient-rich, well-draining, and moist. A pH range of 6-7 is recommended. It is important to avoid planting in soil that is waterlogged since it will cause the roots to rot. Adding organic matter, such as compost or peat moss, to the soil helps with moisture retention and provides necessary nutrients for the plant to grow effectively.
Cultivation Methods
Nasturtium amphibium (L.) Ait. f. is best planted in a cool and wet climate, and it prefers sandy or gravelly soil, as well as a partially submerged location. This species can grow in shallow water up to 15cm in depth or on wet ground. Plant them in early spring, before the onset of long and warm temperatures. Plant the seeds up to 1 cm deep, at a distance of 10-15 cm apart. Nasturtium amphibium (L.) Ait. f. has slow growth, and it usually takes 3-4 years to reach full maturity.
Watering Needs
Nasturtium amphibium (L.) Ait. f. requires enough water to keep it moist. When planted in shallow water, the plant can use the water moisture to its advantage, but the water may prove to be insufficient in very warm and dry areas. Therefore, regular watering is vital, especially during dry spells. Remember to avoid waterlogging, which can damage this species if the water stagnates for too long.
Fertilization
Although not necessary, fertilizing Nasturtium amphibium (L.) Ait. f. can enhance the growth rate and promote healthy foliage. Consider using organic fertilizers, such as compost or farmyard manure, since they are gentler on the plant and minimize the risk of over-fertilization. Apply the fertilizer once every growing season, preferably in early spring.
Pruning
Pruning is not necessary for Nasturtium amphibium (L.) Ait. f. since it is slow-growing and can reach full maturity over a few years. Moreover, this species is not fussy when left to its own devices, and it does not require much attention as long as soil and water requirements are met adequately. However, pruning can help control the plant's spread if necessary, especially in small garden ponds or shallow water bodies. Trim back any overgrown or damaged foliage to promote a healthier, more vigorous plant.
Propagation of Nasturtium Amphibium
Nasturtium amphibium (L.) Ait. f., commonly known as watercress, is a semi-aquatic plant that grows in the shallow water of streams, ponds, and ditches. It is a perennial herbaceous plant that comes under the family Brassicaceae. The leaves of watercress are used as salad greens and have a tangy and peppery taste. Nasturtium amphibium can be propagated by four different methods; these include seed propagation, stem cutting, division, and by rooting the cuttings in water.
Seed Propagation
Starting from seed is the easiest and most common way to propagate watercress. Seeds are readily available commercially or can be collected from mature plants. The seeds need to be planted in a moist environment that is continuously submerged in water.
Seeds can be started indoors in a growing tray, and once they have developed, they can be transplanted into water-filled containers. It takes 10-14 days for the seeds to germinate, and the plants will be ready for harvest in three to four weeks.
Stem Cutting Propagation
Stem cutting propagation is an effective way to propagate watercress. The stems can be snipped off just below the leaf node and should be planted immediately. When planting stems, make sure that at least one node is submerged in water to encourage rooting and growth. The cuttings will root within a week and will be ready for harvest in 3-4 weeks.
Division Propagation
Division propagation is a simple technique for propagating watercress. This method entails separating mature plants into smaller sections and replanting them to create new plants. This method is best done in spring or fall when the plant is least active.
To divide the plant, carefully dig up the roots and separate the plant into manageable sections. Replant each section in water or damp soil and leave undisturbed for a few weeks until you see new growth.
Propagating by rooting the cuttings in water
Planting watercress cuttings in water is a fast and simple method for propagation. Take a healthy cutting and place it in a glass of water, with the leafy end above water and a node submerged underwater. Within 10-15 days, roots should start to grow from the submerged nodes, and the plant can be replanted in the soil or a water container.
Propagation of Nasturtium amphibium is easy and can be done by seed, stem cuttings, division, or rooting the cuttings in water. Once established, watercress will readily propagate and grow, providing a beautiful addition to any garden or aquatic environment.
Disease and Pest Management for Nasturtium amphibium (L.) Ait. f.
Nasturtium amphibium (L.) Ait. f. is a popular aquatic plant known for its attractive foliage and bright flowers. However, like many plants, it is susceptible to a variety of disease and pest problems. Here are some common diseases and pests that might affect Nasturtium amphibium and ways to manage them:
Diseases
Pythium Root Rot: This is a common disease that affects many aquatic plants, including Nasturtium amphibium. It is caused by a water-borne fungus that attacks the roots of the plant, leading to stunted growth and even death. To manage this disease, remove infected plants and avoid over-watering.
Leaf Spot: Leaf spots are caused by a variety of fungal and bacterial pathogens, and they can cause unsightly spotting on the leaves of Nasturtium amphibium. To manage leaf spot, remove infected leaves and provide good air circulation around the plants.
Pests
Aphids: These tiny insects can infest Nasturtium amphibium, sucking the sap from the leaves and causing distortion and yellowing. To manage aphids, use an insecticidal soap or blast them off the plant with water.
Snails and Slugs: These mollusks are common pests that can feed on the leaves and stems of Nasturtium amphibium. To manage snails and slugs, use traps or chemical baits, and remove any debris or hiding places near the plants.
Overall, proper maintenance and care can help prevent disease and pest problems with Nasturtium amphibium. This includes providing adequate drainage, avoiding over-fertilization, and pruning dead or damaged foliage regularly.
