Welcome to the summary page for FabulousFusionFood's Wild Food guide to Japanese Knotweed along with all the Japanese Knotweed containing recipes presented on this site, with 14 recipes in total.

This is a continuation of an entire series of pages that will, I hope, allow my visitors to better navigate this site. As well as displaying recipes by name, country and region of origin I am now planning a whole series of pages where recipes can be located by meal type and main ingredient. This page gives a listing of all the Cornish recipes added to this site.

These recipes, all contain Japanese Knotweed as a major wild food ingredient.

Japanese knotweed, Reynoutria japonica (syn Polygonum cuspidatum, Fallopia japonica), also known as: Fleeceflower, Huzhang (Chinese: 虎杖; pinyin: Hǔzhàng), Hancock's curse, Elephant Ears, Donkey Rhubarb (although it is not a rhubarb), Sally Rhubarb, Japanese bamboo, American bamboo, and Mexican bamboo (though it is not a bamboo) is a member of the family Polygonaceae (knotweed or smartweed). It is a large, herbaceous perennial plant, native to eastern Asia in Japan, China and Korea. It has been extensively introduced into the U.S.A. and Europe where the species has been very successful and has become very invasive in several countries.

The flowers are small, cream or white, produced in erect racemes 6–15 cm (2+1⁄2–6 in) long in late summer and early autumn. Japanese knotweed has hollow stems with distinct raised nodes that give it the appearance of bamboo, though it is not related. While stems may reach a maximum height of 3–4 m (10–13 ft) each growing season, it is typical to see much smaller plants in places where they sprout through cracks in the pavement or are repeatedly cut down. The leaves are broad oval with a truncated base, 7–14 cm (3–5+1⁄2 in) long and 5–12 cm (2–4+1⁄2 in) broad,[8] with an entire margin. New leaves of Reynoutria japonica are dark red and 1 to 4 cm (1⁄2 to 1+1⁄2 in) long; young leaves are green and rolled back with dark red veins; leaves are green and shaped like a heart flattened at the base, or a shield, and are usually around 12 cm (5 in) long.

Mature R. japonica forms 2-to-3-metre-tall (6+1⁄2 to 10 ft), dense thickets. Leaves shoot from the stem nodes alternately in a zigzag pattern. Plants that are immature or affected by mowing and other restrictions have much thinner and shorter stems than mature stands, and are not hollow.

The young stems are edible as a spring vegetable, with a flavour similar to mild rhubarb. In some locations, semi-cultivating Japanese knotweed for food has been used as a means of controlling knotweed populations that invade sensitive wetland areas and drive out the native vegetation. Knotweed shoots can be used in both sweet and savoury dishes.

Indeed, very young Japanese knotweed shoots can be used as an asparagus substitute. Older stems and shoot tips can be peeled and served cooked. These taste like a milder version of rhubarb. The seed, though fiddly to harvest can be eaten raw or cooked. When toasted and ground to a powder the seed can be used as a flavouring or thickener in soups and stews or mixed with grains to make bread, cakes and biscuits. In Japan, the root is sometimes boiled and served as a vegetable.

Japanese knotweed can be an acquired taste, for a couple of reasons. The flavour is like mild rhubarb, but with a noticeable earthy overtone. It pairs well with members of the apple family: apples, pears, quinces (or white grapes) unlike rhubarb that pairs best with ripe red fruit. There is also the mucilage: As the shoots cook, or even if they're exposed to water, they turn slimy, quick. Cooking mellows the slime, but the texture of the hollow stems is not pleasant for many people (unless you're used to West African style cookery).

Unless the shoots are very tender, the outer layer should be peeled. This mellows the flavour (the skin has a much stronger flavour than the inner stems). As the plant ages they become more fibrous and stringy. Most of the fibres are in the skin, so removing this reduces the fibrousness of the final product.

Fermenting of pickling knotweed is the best way of preparing for a beginner (lacto-fermented knotweed is excellent). The next most approachable method of cooking is to cook down to a smooth, lightly-sweetened puree. The leaves tend to be much stronger and more fibrous than the stems, so discard these before cooking.

A note on discarding knotweed: like bamboo, it's very hard to get rid of and if you accidentally put pieces of knotweed stems in your compost it will root and grow so I would strongly recommend killing any left-over knotweed by boiling or microwaving before discarding.

References:

[1]. David Evans Notes from field observations, tastings and cookery experiments.
[2]. Huxley, A. The New RHS Dictionary of Gardening. 1992
[3]. Tanaka, T. Tanaka's Cyclopaedia of Edible Plants of the World.
[4]. Lim T.K. Edible Medicinal And Non-Medicinal Plants, Vols 1–8.
[5]. Thomas, G. S. Perennial Garden Plants
[6]. Milner, E. Trees of Britain and Ireland
[7]. Rose, F. & O'Reilly, C. The Wild Flower Key (Revised Edition) – How to identify wild plants, trees and shrubs in Britain and Ireland
[8]. Streeter, D. & Garrard, I. The Wild Flowers of the British Isles
[9]. Clapham, A.R.; Tutin, T.G. & Moore, D.M. Flora of the British Isles
[10]. Phillips, R. Mushrooms
[10]. Phillips, R. Mushrooms
[11]. Jordan, P. & Wheeler, S. The Complete Book of Mushrooms: An Illustrated Encyclopedia of Edible Mushrooms
[12]. Bunker, F.; Brodie, J.A.; Maggs, C.A. & Bunker, A. Seaweeds of Britain and Ireland.
[13]. Facciola, S. Cornucopia — A Source Book of Edible Plants