Houttuynia cordata Seeds | Tea Fish Mint Tea
LATIN NAME: Houttuynia cordata
COMMON NAME: Fish Mint
Plant Profile
Fish mint spreads by thin runners just under the soil, throwing up heart-shaped leaves on upright stalks. What looks like a flower is a short spike of tiny green-yellow true florets backed by four white leaf-like bracts, the showy part that reads as a single bloom. The whole plant leans toward moisture and shrinks from dry air, which is why it sulks in a hot border but glows by a pond.
The leaf blade is blunt and cordate, often with a red streak down the centre in some forms. The runners let one plant carpet a damp border by the end of a warm season, which is a gift in the bog garden and a headache in the neat bed, where the same runner slips under a path and appears two feet away by the following spring.
Gardeners grow a yellow-edged form, ‘Chameleon’, for colour alone, since its bite is milder than the plain green type. It still runs, so contain it in a pot or a sunken ring if you want a tidy patch, and cut the plain green shoots out of the pot because they will outgrow the variegated one given half a chance.
The pungent oil that gives fish mint its name also gives it a place in the insect world, because the same volatiles that humans find stark repel a range of leaf eaters in the home plot. That is one reason the plant thrives where tender herbs fail, and why a patch by the vegetable garden pulls double duty as a border and a quiet bodyguard. The variegated form trades some of that strength for colour, so the grower chooses between show and bite depending on the bed. Either way the runner keeps the plant coming back, and a single pot by the step becomes a lasting supply with almost no care through the warm season.
Science & Biotechnology
The leaf carries quercitrin and related flavonoids, the markers behind the Chinese name Yu xing cao, which means ‘fish-smell grass’. The smell itself comes from a volatile mix led by decanoyl acetaldehyde, a compound studied for its antimicrobial action, and the strength of that smell tracks the strength of the oil across the season.
Extract work follows hyperin (hyperoside) and quercitrin through leaf and stem, with interest in antioxidant and anti-inflammatory lines. Tissue culture offers a way to bulk up selected high-flavonoid clones without stripping stream banks, and the plant’s weedy vigour makes it a willing subject for a small propagation cabinet in a teaching lab.
A brief steep of the leaf makes a pale, sharp tisane taken in hot weather. As a landscape plant it earns its keep as a shade-tolerant ground cover where little else stays green and low by the water, and a single planted pot will, left to its own devices, soon become a solid mat of heart-shaped leaves.
Uses & Benefits
This family is small and odd, with no close culinary look-alikes, which is why the flavour is its own signature. That isolation makes fish mint a useful teaching plant for anyone learning plant families by taste and smell, because nothing else in the herb garden prepares you for the particular note it leaves on the tongue.
In Vietnam the raw leaf goes into herb plates with noodle soups and hotpot; in China it is a cooling summer green and a traditional tea. The fresh sprig is the seasoning, added at the table rather than cooked long, because heat drives off the volatile that makes the herb worth using in the first place.
Growing from Seed
Give fish mint wet, humus-rich soil and part to full shade; it sulks in dry sun and the leaves turn thin and bitter. A pot in a saucer of water is the easiest way to keep a supply by the kitchen door, and the pot also keeps the runners from escaping into the rest of the garden.
Divide the running clump in the cool season and pot the pieces, or simply cut the runners back at the edge to hold the patch. In a dry summer keep the saucer filled so the leaves stay tender and the pungency stays mild, because a thirsty plant turns sharply medicinal in a way few eaters enjoy.
Our Take
I keep fish mint in a sunk pot by the rain barrel, where the runners hit the wall and stop. If you want aromatic leaf herbs from the same Asian-kitchen shelf, the purple perilla and the cilantro are natural neighbours: see Purple Perilla and Cilantro, and for a calm citrus note try Lemon Balm.
Related Reading
More species in the same orbit as Fish Mint: