Fishwort, botanically Houttuynia cordata, is a distinctive herb for gardens and culinary uses. It is also known as Chameleon Plant, Heartleaf, and Fish Mint, reflecting its varied appearance and pungent aroma. Originating in East Asia, fishwort is popular in specific regions for its unique flavor and traditional applications.
Understanding Fishwort
Houttuynia cordata is a herbaceous perennial in the Saururaceae family, known for its creeping nature and vigorous spread. It features heart-shaped leaves that can display green, purple, red, or variegated patterns. Small, inconspicuous greenish-white flowers, subtended by four showy white petal-like bracts, usually appear from late spring to mid-summer.
This plant thrives in moist, shady environments, often found along riverbanks or in wet fields across its native East Asia, including China, Japan, Korea, and Southeast Asia. The common name “fishwort” or “fish mint” comes from its distinct, strong fishy aroma when the leaves are crushed, attributed to sulfurous compounds in its volatile oils.
Culinary Uses of Fishwort
Fishwort is a staple in Southeast Asian and East Asian cuisines, celebrated for its unique, assertive flavor. It is often described as pungent, citrusy, and slightly fishy, with peppery undertones, making it an acquired taste for some. The leaves are predominantly used fresh, adding zest to dishes.
In Vietnamese cuisine, fishwort, known as “diếp cá,” is a popular fresh herbal garnish for grilled meats, spring rolls, and noodle salads. In northeastern India, the leaves are commonly incorporated into salads, salsas, and cooked with other vegetables, or used as a garnish. The tender roots, known as “Zhé’ěrgēn” in southwestern China, are also consumed as a root vegetable, often fried with cured pork belly or used in dipping sauces for noodles and tofu.
Traditional Medicinal Applications
For centuries, fishwort has been used in traditional folk medicine, particularly in Traditional Chinese Medicine (TCM) and other Asian herbal practices. Traditionally, it has been employed for various ailments, especially respiratory issues like pneumonia, lung abscesses, coughs, and fevers. It has also been used for infections, detoxification, dysentery, and mumps.
During the 2003 SARS outbreak, Houttuynia cordata was listed as a traditional remedy in China, highlighting its cultural relevance. These are traditional uses based on historical practices and are not necessarily supported by modern clinical research.
Growing Fishwort
Cultivating fishwort is straightforward due to its adaptability and vigor. It prefers consistently moist to wet soil and can tolerate shallow standing water, making it suitable for bog gardens or pond margins. While it grows in full shade, its characteristic variegated foliage, especially in ‘Chameleon’ varieties, develops brightest colors in full sun or bright, indirect light.
Fishwort can be propagated from seeds, stem cuttings, or by dividing its rhizomes, which is often the most successful method. It spreads aggressively via rhizomes and can become invasive, potentially displacing native plants. Regular monitoring and pruning are necessary to control its spread, or it can be grown in containers. Leaves can be harvested throughout the growing season as needed for culinary or traditional uses.
Potential Health Benefits and Precautions
Scientific investigations into Houttuynia cordata have explored its potential health properties. Research indicates bioactive compounds that may contribute to antioxidant, anti-inflammatory, and antimicrobial effects, with some studies suggesting antiviral activity. While promising, much of this research is in early stages, often in laboratory or animal settings; human studies are needed to confirm benefits.
Caution is advised when considering fishwort for medicinal purposes. Potential side effects include allergic reactions, gastrointestinal discomfort (e.g., nausea, diarrhea), and in some cases, liver toxicity, especially with high doses or certain extracts. Fishwort also contains oxalates, which may concern individuals on low-oxalate diets. Pregnant or nursing individuals should avoid its use. Always consult a healthcare professional before using fishwort for medicinal applications, particularly if taking other medications.