Fish Mint
Houttuynia cordata
Fish Mint (Houttuynia cordata), also known as Chameleon Plant, Heartleaf, or Yuxingcao in Chinese, is a distinctive perennial herbaceous plant in the family Saururaceae. It is the sole species in the genus Houttuynia, making it a monotypic genus of considerable botanical interest.
The plant is instantly recognizable by its pungent, fishy aroma — a scent so polarizing that it has earned both devoted admirers and fierce detractors across its native range. Despite (or perhaps because of) this unusual fragrance, fish mint has been used for centuries as both a culinary herb and a traditional medicinal plant throughout East and Southeast Asia.
• The genus name Houttuynia honors the Dutch naturalist Martinus Houttuyn (1720–1798)
• The species epithet cordata refers to the distinctly heart-shaped (cordate) leaves
• It is one of the few plants whose scent is commonly described as "fishy" — caused primarily by the volatile compound decanoyl acetaldehyde (2-oxododecanal)
• Known by dozens of regional common names including "fish wort," "bishop's weed," "dokudami" (Japan), "eoseongcho" (Korea), and "phakbung" (Thailand)
Taxonomy
• Native range spans from Nepal and northeastern India through southern and eastern China, the Korean Peninsula, Japan, and into Indochina
• Thrives at elevations from near sea level up to approximately 2,500 meters in montane regions
• Has been introduced to and naturalized in parts of North America and Europe, where it is sometimes considered an invasive species due to its vigorous spreading habit
• In its native habitat, it commonly colonizes the margins of streams, ditches, wet meadows, and forest edges
The plant has a long history of use in traditional medicine systems:
• Documented in Chinese herbal medicine for over 2,000 years, with references in classical texts such as the Mingyi Bielu (Miscellaneous Records of Famous Physicians)
• In Japanese traditional medicine (Kampo), the dried leaves are known as "dokudami" and are used in herbal formulations
• In Korean traditional medicine, it is called "eoseongcho" and has been used as an anti-inflammatory and detoxifying agent
Rhizome & Stems:
• Spreads aggressively via slender, creeping rhizomes (stolons) that root at the nodes
• Rhizomes are yellowish-white, fleshy, and can extend several meters in a single growing season
• Erect flowering stems are slender, typically 15–40 cm tall, green to reddish-green, and glabrous or sparsely pubescent
Leaves:
• Simple, alternate, broadly cordate (heart-shaped), 3–8 cm long and 3–6 cm wide
• Leaf margins are entire (smooth-edged); base deeply cordate; apex acute to obtuse
• Upper surface is dark green, sometimes with irregular reddish or purplish blotches; lower surface often paler with purplish tinge
• Petioles are relatively long (1–5 cm), sheathing at the base
• When crushed, leaves release the characteristic pungent, fishy odor
Flowers & Inflorescence:
• Flowers are tiny, inconspicuous, and lack true petals and sepals
• Arranged in dense terminal spikes (spadix-like), 1.5–3 cm long, borne on peduncles 1.5–3 cm long
• Each flower consists of 3–4 stamens and a superior ovary
• The most visually striking feature is the conspicuous white involucre of 4–6 petaloid bracts (often mistaken for petals), each obovate, ~1.5–2 cm long, giving the inflorescence a clean white appearance
• Flowering period: typically April to October in temperate regions, nearly year-round in tropical climates
Fruit & Seeds:
• Fruit is a capsule that dehisces (splits open) to release numerous minute seeds
• Seeds are small, ellipsoid, and possess an oily appendage (elaiosome) that attracts ants, facilitating myrmecochory (ant-mediated seed dispersal)
Habitat Preferences:
• Stream banks, river margins, and the edges of ponds and ditches
• Wet meadows, marshes, and swampy forest clearings
• Shaded to semi-shaded locations with consistently moist to wet soil
• Frequently found in disturbed areas, along trails, and at the margins of agricultural fields
Light:
• Prefers partial shade to dappled sunlight
• Can tolerate full shade but may produce fewer flowers
• In full sun, leaves may scorch unless soil moisture is consistently high
Soil:
• Thrives in rich, loamy, moisture-retentive soils
• Tolerates a range of soil pH from slightly acidic to slightly alkaline (pH 5.5–7.5)
• Can grow in sandy or clay soils provided adequate moisture is maintained
Water:
• Requires consistently moist to wet soil; does not tolerate drought
• Can tolerate brief periods of shallow standing water
• Ideal for rain gardens, bog gardens, and waterside plantings
Reproduction & Spread:
• Reproduces both sexually (by seed) and vegetatively (by rhizome fragmentation)
• Vegetative spread is the primary mode of colonization — even small rhizome fragments can regenerate into new plants
• This aggressive spreading habit makes it potentially invasive outside its native range
• In North America, it is listed as an invasive species in several states
Ecological Interactions:
• Flowers are pollinated by small insects, including flies and beetles
• Seeds are dispersed by ants (myrmecochory) and by water
• Provides ground cover habitat for small invertebrates
• Some butterfly and moth species use it as a larval host plant in its native range
Light:
• Partial shade to dappled sunlight is ideal
• Tolerates full shade with reduced flowering
• Can grow in full sun if soil moisture is consistently maintained
Soil:
• Rich, loamy, moisture-retentive soil is optimal
• Tolerates a wide range of soil types including clay, loam, and sandy soils
• Soil pH: 5.5–7.5 (slightly acidic to slightly alkaline)
• Benefits from the addition of compost or well-rotted organic matter
Watering:
• Keep soil consistently moist at all times; this is the single most important cultural requirement
• Can tolerate shallow standing water, making it suitable for bog gardens and pond margins
• Will wilt rapidly if allowed to dry out, though it typically recovers quickly upon rewatering
Temperature:
• Hardy in USDA zones 4–11 (tolerates winter temperatures down to approximately −30°C when dormant)
• Dies back to the rhizome in winter in temperate climates; regrows vigorously in spring
• Evergreen or semi-evergreen in mild winter climates
Propagation:
• Division of rhizomes is the easiest and most reliable method — simply dig up a section of rhizome with attached roots and replant
• Stem cuttings root readily in moist soil or water
• Seed propagation is possible but rarely necessary given the plant's vigorous vegetative spread
Containment:
• Strongly recommended to plant in containers, raised beds with barriers, or confined garden areas
• Rhizomes can spread 1–2 meters or more per growing season if unchecked
• Underground barriers (at least 30 cm deep) can help prevent unwanted spread
Common Problems:
• Generally pest- and disease-free
• Slugs and snails may occasionally feed on young leaves
• Overwatering is rarely an issue given the plant's wetland nature
• The main "problem" is its aggressive spreading habit
Fun Fact
Fish mint's extraordinary fishy smell has a fascinating chemical explanation — and a surprising twist: • The characteristic odor is primarily caused by decanoyl acetaldehyde (2-oxododecanal), a volatile compound released when the leaves are crushed or damaged • This same compound is found in certain fish, which is why the plant smells "fishy" to the human nose • Interestingly, the fishy aroma largely dissipates when the leaves are cooked or dried, leaving a milder, more palatable flavor A Plant of Many Cultural Identities: • In China, the herb known as "yuxingcao" (fish-fragrant herb) is a staple of Sichuan and Guizhou provincial cuisines, used fresh in salads, stir-fries, and as a garnish • In Vietnam, the leaves (known as "diếp cá") are a beloved accompaniment to grilled meats and spring rolls • In Japan, "dokudami" tea (dekutocha) is a popular summer beverage believed to have detoxifying properties • The Japanese name "dokudami" literally means "poison-blocking plant," reflecting its traditional reputation as an antidote Antibiotic Discovery: • In 1942, Japanese researchers isolated sodium houttuyfonate from fish mint, which demonstrated antibacterial properties • This discovery contributed to the development of synthetic derivatives used as antibiotic adjuvants in some traditional Chinese medicine formulations Survivor of the Atomic Bomb: • Fish mint is reputed to be one of the first plants to regrow in Hiroshima after the atomic bombing in 1945 • While this claim is difficult to verify with certainty, the plant's extraordinary resilience — its ability to regenerate from tiny rhizome fragments and tolerate harsh conditions — lends the story a certain botanical plausibility The Chameleon Plant: • One of its common names, "Chameleon Plant," refers to cultivars with variegated leaves displaying splashes of red, pink, cream, and green • The cultivar 'Chameleon' (H. cordata 'Chameleon') is grown primarily as an ornamental ground cover for its colorful foliage, though it is less vigorous than the plain green species
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