Japanese Knotweed Identification Tips at Different Stages


The Japanese knotweed is the most invasive plant species known for its rapid growth.  It’s distinguished from similar weeds by its huge size, which can go up to four meters high. The roots penetrate deep into the ground by up to three meters and branch out seven meters horizontally. When young, Japanese knotweed has almost the same size of leaves found in most woody scrubs, and so, identifying it may prove a great challenge. Let’s discuss some Japanese knotweed identification tips at different stages.

Identifying Knotweed in spring

Japanese knotweed starts growing in spring, and it’s during this period the weed grows super-fast and efficiently. During this initial growth stage, the weed has purple/red tinge stems and rolled up leaves. As the season ages towards summer, the canes will sprout from the ground, while the leaves will open up, turning to a light green color. If the weed in your garden has any of these characteristics, you should know right away that it’s in its initial growth stage.

Identifying the Weed in summer

The fresh canes that had just developed in spring will become flattered and sprout bamboo-like looks. The stems will develop discernable purple flecks, while the leaves will grow zig-zag shapes. Also, the leaves will become flat and green with a heart shape highlighted by mid-rids and veins. During the summer season, the plant will have little creamy-white flowers, which will bloom by the end of August.

Identifying the Weed in Autumn

During the start of autumn, the Japanese knotweed will have bunches of flowers and densely-congested shovel-shaped leaves. The flowers will still have some creamy-white color, while the leaves still have healthy and green. As autumn ages, the weed’s leaves will develop a yellow color, while the plant will grow to around 3 meters.  The bamboo-like canes will turn from the reddish-brown color to dark brown shade.

Identifying the Weed in winter

When winter starts, the plant will go dormant with the canes turning dark brown and hollow. The witted yellow leaves will become smaller, while the canes will brittle, snap, and collapse, leaving some debris in the weed’s place, During winter, the weed will have overgrown and easily identifiable.

One tricky activity you can engage in as a farmer or homeowner is to identify Japanese knotweed. The chances of getting confused and making mistakes during Japanese knotweed identification at the late stages are high. Eradicating the weed during its early stages is easier and guarantees results since it’s still very young and does not have the longest and strongest of roots. The spring is when the weed starts growing, and so, identifying and removing it at this early stage is highly recommended. Don’t wait until winter when it would have grown so big and impossible to remove.

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