Japanese knotweed

Japanese knotweed is one of the most aggressively invasive plants in Denmark and can take over large expanses of land. Picking it, then, is actually a conservation measure. But very few people know that it's also delicious ingredient that tastes a lot like rhubarb.

  • Where to Find It

    Japanese knotweed prefers to grow in moist, nutrient-rich soil at the edge of deciduous forests or on the banks of streams or lakes. It also takes hold in parks and on the outskirts of construction sites. If allowed to spread, it can cover large areas and grow into small forests.

  • Streams, lakes, deciduous forests, towns, hedges, roadsides, grasslands.
  • When to Find It

    Japanese knotweed is best in April and May, when it shoots up 5-10 cm a day. If cut down regularly over the course of spring and early summer, it will continue to sprout new shoots until July or even August.

  • Young shoots: April, May.
    Entire plant: April, May, June, July.
  • How to Spot It

    Japanese knotweed has a hollow, red-spotted stem that can grow to be up to two and a half meters tall. Its broad, oval-shaped leaves form a small point at the tip. The stem is jointed and looks like thick, green bamboo. The new shoots are 10-50 cm tall and look succulent, with reddish leaves. Japanese knotweed develops small, white flowers that grow in clusters along spiked stems at the top of the herb.

  • How to Pick It

    The new stems are tender and succulent; the place where the plant turns fibrous, hard, and tasteless is usually visible. Using a knife, cut off the new shoots in a spot where you think the stem is still tender. When the plant gets older, you can pick its soft, succulent top around 30 cm from the top. You can also use leaves that are slightly older. Remember not to throw the unwanted parts of the plant back into nature or put them into compost, as even the smallest piece will quickly propagate.

Risk of misidentifying the plant

There is no risk of mistaking the plant for another dangerous or undesirable plant.