Origin
Nasturtium sarmentosum (G. Forst. ex DC.) Schinz & Guillaumin, commonly known as creeping Nasturtium, belongs to the family Tropaeolaceae and is native to Polynesia, Melanesia, and Southeast Asia.
Common Names
The plant is known by several common names in different regions including creeping Nasturtium, trailing watercress, running Nasturtium, and Creeping cress. In Tahiti it's known as Pauroro and in Fiji as Ivikana.
Uses
The plant has several uses in traditional medicine as it contains glucosinolates, which have been shown to have anti-inflammatory and anti-cancer properties. In the Pacific Islands, it is widely used as a medicinal plant to treat coughs, sore throats, and infections. The leaves and stems are also used as a spice and vegetable in various dishes, providing a peppery taste similar to watercress.
General Appearance
Nasturtium sarmentosum is a perennial herb that grows up to 1m in length. The plant has glossy, green leaves that are 2-6 cm wide and 3-18 cm long, with a rounded to a slightly lobed shape. The leaves grow on long, slender stems that trail along the ground or climb on surrounding vegetation. The plant produces small yellow flowers and a small seedpod.
Light Requirements
Nasturtium sarmentosum is a plant that thrives in full sunlight. It can grow well in partially shaded areas, but it will not produce as many flowers or leaves as those grown in full sun. Therefore, it is recommended to grow this plant in areas that receive a minimum of six hours of direct sunlight per day.
Temperature Requirements
The ideal temperature range for Nasturtium sarmentosum varies between 15°C to 25°C. However, it can tolerate temperatures above or below that range, but it may affect the growth rate and overall health of the plant. This plant can withstand light frosts, but it cannot tolerate extended periods of freezing temperatures. Therefore, it is recommended to maintain the plant in a temperature-controlled environment if it is grown in areas with extreme temperature conditions.
Soil Requirements
Nasturtium sarmentosum grows best in well-drained soil that is rich in organic matter. The soil pH should be between 6.5 to 7.5, which is slightly acidic to neutral. The plant can grow in sandy, loamy, or clay soils, as long as it is well-drained and fertile. It is important to maintain consistent moisture levels in the soil, as this plant does not tolerate drought stress well. Therefore, it is recommended to water the plant regularly, particularly during dry spells, to ensure the soil remains moist but not waterlogged.
Cultivation Methods
Nasturtium sarmentosum is a hardy plant that is easy to grow in almost any soil. It can be planted from seeds or cuttings and should be planted in a well-draining soil mix. This plant prefers a sunny or partly shaded environment and can grow moderately well in either dry or humid conditions. It is best planted in spring or fall, and should be grown in containers or pots for small gardens or indoors.
Watering Needs
While Nasturtium sarmentosum prefers moderate watering, it can still grow well in dry conditions. Overwatering should be avoided, so the soil should be allowed to dry out between watering. Ideally, the soil should be moist but not too wet, and watering should be done in the morning or early evening. During the hotter months, frequent watering may be necessary to prevent the plant from drying out.
Fertilization
Nasturtium sarmentosum requires moderate fertilization that should be done at intervals of every two to four weeks. The plant should be fed with an all-purpose fertilizer, and if the soil is poor, an organic fertilizer can be used. The plant may not grow well if it is over-fertilized, so it is essential to use the right amount.
Pruning
Nasturtium sarmentosum can benefit from pruning, especially when it becomes too leggy. You can pinch back the growing tips or remove the lower leaves to encourage bushier growth. Pruning should be done after flowering, in the spring or summer, and can be repeated as often as needed. The plant can also be cut back severely in the spring to stimulate new growth. Deadheading should also be done regularly to encourage more flowers.
Propagation of Nasturtium sarmentosum
Nasturtium sarmentosum (G. Forst. ex DC.) Schinz & Guillaumin, commonly known as creeping or trailing watercress, is a plant species that is native to Polynesia, Melanesia, and Southeast Asia. It is grown for its edible leaves and stems, which have a pungent, peppery taste. The plant is relatively easy to grow and propagate.
Propagation Methods
Nasturtium sarmentosum can be propagated by seed or stem cuttings. Both methods are effective, but stem cuttings are faster and more reliable.
Propagation by Seed: Seeds of Nasturtium sarmentosum can be collected from mature fruits. The seeds are small and brown. They can be directly sown into the soil or started in a seed tray. If starting in a seed tray, use a standard potting mix and keep the soil moist. It is recommended to cover the tray with a plastic bag to maintain soil moisture until germination. The seeds should germinate within two weeks. Once the seedlings are established and have grown their true leaves, they can be transplanted into their permanent location.
Propagation by Stem Cuttings: Stem cuttings are a more efficient method for propagating Nasturtium sarmentosum. Cuttings should be taken from young, healthy shoots. The cuttings should be about 4 to 6 inches long with several leaves attached. Remove the lower leaves of the cutting and dip the cut end in rooting hormone. Plant the cutting in moist potting soil or a mixture of sand and peat moss. Keep the soil moist and in a warm, shady location. The cutting should start to form roots in approximately two weeks.
Regardless of the method chosen, it is important to keep the soil consistently moist and avoid overwatering. Nasturtium sarmentosum prefers well-drained, organic-rich soil and partial shade. Once established, the plant requires little maintenance and readily self-seeds.
Disease management
Nasturtium sarmentosum is generally a healthy plant that is not susceptible to many diseases. However, it can be affected by a few diseases that can cause issues if left untreated. Here are some common diseases that can affect this plant and ways to manage them:
Downy mildew
Downy mildew is a fungal disease that causes yellow or light green spots on leaves. These spots later turn brown and become covered with a white or gray fuzzy growth on the underside of the leaves. The disease can quickly spread and cause significant damage to the plant. To manage downy mildew, avoid overhead watering and provide good air circulation around plants. Fungicides containing copper or mancozeb can also help control the disease.
Root rot
Root rot is a fungal disease caused by overwatering and poor drainage. The disease causes the roots to rot, making it difficult for the plant to absorb water and nutrients. Symptoms of root rot include stunted growth, yellow or wilted leaves, and a foul odor. To manage root rot, improve drainage by planting the nasturtium in well-draining soil and avoiding overwatering. Fungicides may also help, but prevention is the best method of management.
Pest management
Nasturtium sarmentosum can be affected by a range of pests. Here are some common pests that can affect nasturtium and ways to manage them:
Aphids
Aphids are small, pear-shaped insects that feed on the sap of the plant. They can cause stunted growth and yellowing of leaves, as well as the transmission of viruses. To control aphids, spray the plant with a stream of water to dislodge them, or use insecticidal soap or neem oil. Ladybugs, lacewings, and parasitic wasps are natural predators, so encourage their presence in the garden.
Slugs and snails
Slugs and snails are common garden pests that can cause significant damage to nasturtium. They feed on the leaves and flowers, leaving behind unsightly holes and slime trails. To manage slugs and snails, use physical barriers such as copper tape or diatomaceous earth around the plant. You can also handpick them or set out traps baited with beer or yeast.
With proper management techniques, Nasturtium sarmentosum can grow healthy and strong, providing gardeners with beautiful foliage, edible flowers, and a host of beneficial properties.
