Origin
Rorippa curvisiliqua (Hook.) Bess. ex Britt. var. curvisiliqua, commonly known as curly water-cress, is a plant species belonging to the Brassicaceae family. It is native to North America, specifically found in the northeast United States from Maine to Virginia. It can also be found in southeastern Canada.
Common Names
The plant is commonly referred to as curly water-cress, yellow cress, or yellow water-cress.
Uses
Curly water-cress is edible and is often used in salads and as a garnish due to its pleasant, spicy flavor. The plant is also used for medicinal purposes, particularly in treating scurvy, as it is rich in vitamin C. Additionally, it has been used as a substitute for horseradish and as a dye for textiles.
General Appearance
Rorippa curvisiliqua var. curvisiliqua is a perennial plant that typically grows in shallow, slow-moving water or in wet soils. It can reach a height of up to 50cm and has a shallow root system. The plant has small, yellow flowers that bloom from May to July and is often found in colonies. The leaves are alternate, pinnately compound, and have a slightly curly appearance, which gives the plant its common name. The leaves are lanceolate to oblong shaped, and each leaflet is up to 7cm long and 2cm wide. The stem of the plant is greenish-brown and has fine hairs.
Light Requirements
Rorippa curvisiliqua prefers to grow in full or partial sunlight. They can survive in shaded conditions, but the best growth is seen when they receive at least 6 hours of direct sunlight per day. If planted in shaded areas, they tend to grow taller and lean towards sources of light, resulting in weaker stems.
Temperature Requirements
This plant can tolerate a wide range of temperatures, but it grows best with an average temperature of 20-25°C (68-77°F). It can withstand temperatures as low as -10°C (14°F) and as high as 40°C (104°F) for short periods of time, but prolonged exposure to extreme temperatures can stunt growth or kill the plant.
Soil Requirements
Rorippa curvisiliqua prefers moist, well-drained soils rich in organic matter. They can grow in a variety of soil types, including sandy and clay soils, but the best growth is seen in neutral to slightly acidic soils with a pH range of 6.0-7.5. The soil should be kept consistently moist, so planting in areas with good water retention or using mulch to retain moisture can be beneficial for growth.
Cultivation
Rorippa curvisiliqua is a hardy perennial native to North America that prefers moist soil and partial shade. It can be grown successfully in USDA hardiness zones 3-8 and is typically started from seed.
Watering Needs
The plant requires consistent watering to maintain soil moisture levels, but it should not be allowed to sit in standing water. Water thoroughly once a week, unless rainfall is adequate, and allow the soil to dry slightly between watering sessions. Deep watering at the base of the plant is preferable to overhead watering, as it reduces the risk of leaf diseases.
Fertilization
While Rorippa curvisiliqua does not require heavy fertilization, a light feeding in the spring with a balanced fertilizer can aid the plant's growth and development. Apply no more than 1-2 tablespoons of a slow-release fertilizer around the base of each plant. Too much fertilizer can lead to excessive foliage growth and reduced flowering.
Pruning
Pruning Rorippa curvisiliqua could cause adverse effects on its growth patterns. This plant responds well to being allowed to grow naturally and should not require pruning. Deadheading or removing spent flowers as needed can encourage the production of new flowers.
Propagation of Rorippa curvisiliqua
Rorippa curvisiliqua (Hook.) Bess. ex Britt. var. curvisiliqua, commonly known as yellow cress or spreading yellow cress, can be propagated through seeds or cuttings. Both methods have their advantages and disadvantages.
Propagation by Seeds
Propagation by seeds is the most common and easiest way to propagate yellow cress. The seeds can be collected from mature plants and stored in a cool, dry place until sowing time. Seeds should be sown in a moist, well-draining soil mix and kept in a warm, bright location until germination occurs. The soil should be kept consistently moist, but not waterlogged. Thin the seedlings once they have grown to avoid overcrowding and promote healthy growth. Seed propagation can be done either indoors or outdoors, depending on the climate and growing conditions.
Propagation by Cuttings
Propagation by cuttings is a bit trickier than seed propagation, but it can be a useful method for those who have limited seeds or want to maintain a particular cultivar of yellow cress. To propagate by cuttings, select a healthy stem that is at least several inches long and has several sets of leaves. Cut the stem just below a node (where a leaf meets the stem) and remove the leaves from the lower portion of the stem. Dip the cut end of the stem in rooting hormone and plant it in a moist soil mix. Cover the cutting with plastic to create a humid environment and keep the soil consistently moist. Roots should begin to form in a few weeks. Once roots have developed, the cutting can be transplanted to a larger container or directly into the garden.
Regardless of the propagation method chosen, it is important to maintain consistent moisture in the soil and provide the yellow cress with adequate light for healthy growth. With proper care and attention, yellow cress can thrive and spread, providing a beautiful addition to any garden or landscape.
Disease Management
Rorippa curvisiliqua var. curvisiliqua is prone to several diseases, including:
Blackleg
Blackleg is caused by a fungus called Phoma lingam. It infects the stem and causes the plant to wilt. To manage blackleg, remove diseased plant parts, practice crop rotation, and avoid planting in areas where the disease has been before.
Clubroot
Clubroot is caused by Plasmodiophora brassicae, a soil-borne pathogen. The disease causes the roots to swell, giving them a club-like appearance. To manage clubroot, practice crop rotation, avoid planting in infected areas, and apply lime to the soil to raise the pH.
Sclerotinia Stem Rot
Sclerotinia stem rot is caused by Sclerotinia sclerotiorum. It causes the stem to rot, and the plant dies. To manage this disease, remove infected plant parts, practice crop rotation with non-brassica crops, and use fungicides if necessary.
Pest Management
Rorippa curvisiliqua var. curvisiliqua is also prone to several pests, including:
Cabbage Aphids
Cabbage aphids damage the plant by sucking sap from the leaves and stems. To manage cabbage aphids, introduce natural predators such as ladybugs, use insecticidal soaps, or spray the plant with a solution of water and dish soap.
Cabbage Loopers
Cabbage loopers are caterpillars that eat leaves, causing large holes. To manage cabbage loopers, introduce natural predators such as birds, use insecticidal soaps, or spray the plant with Bacillus thuringiensis (Bt) which is a natural bacteria that kills the caterpillars.
Harlequin Bugs
Harlequin bugs suck sap from the plant, and their feeding causes the leaves to wilt. To manage harlequin bugs, introduce natural predators such as spiders, use insecticidal soaps, or spray the plant with neem oil.
