Japanese Knotweed: The Monstrous Plants and Its Identification

Japanese Knotweed The Monstrous Plants and Its Identification

Japanese knotweed is one of the most hated weed plants here in North America. They are the monstrous and persistent type of weed. Getting rid of these plants will require lots of effort in order to prevent them from a re-growth process.

But how sure you are that the one you spotted is the real Japanese knotweed? Don’t worry, this article will serve as a guide to give you knowledge about japanese knotweed identification. Generally speaking, thousands of photos are being sent to several eradicating companies suspecting that they have Japanese knotweed on their backyard.

So to avoid you from suspecting these innocent plants like Japanese knotweed, below are some valuable information you should keep in your mind on how to spot the real Japanese knotweed.

japanese knotweed identification

The Best Time to Catch the Real Japanese Knotweed 

The best time to spot the real and actual Japanese knotweed is during the mid-summer and early autumn seasons. During the spring season, its reddish-purple sprout appears right from the ground, its asparagus-type spears are quickly evolving to bright pink crown-like buds. In fact, these weeds have the ability to grow up to 2cm a day and soon will develop the bamboo-like stems that have green heart-shaped leaves on it.

During the early summer season, a mature Japanese knotweed bamboo-like stems have purple speckles on it, and they can grow up to three meters by height. As for the heart-shaped leaves, it produces a knotweed zigzag pattern.

Japanese knotweed flowers during the late summer have a creamy-white color and might appear lengthy spikey formation. It spreads simultaneously from the underground roots which will become sleep but preparing to be alive during the winter season.

Japanese Knotweed Leaves 

  • New leaves are dark red (not hear-shaped) and have a measurement of 1 up to 4cm long
  • Young leave has a light to moderate dark green and has dark red veins on it
  • Mature leaves are fully grown heart-shaped but flattened leave and have the usual measurement of around 12 cm long 

Japanese Knotweed Stems and Its Features 

  • Mature Japanese knotweeds stems have a measurement of 2m to 3m tall
  • The stems can be easily identified as bamboo-like stems which have purple speckles on it
  • Leaves buds have a zigzag pattern

Japanese Knotweed Flowers Characteristics 

  • Japanese knotweed flowers only bloom during the late summer season between late August and early September
  • The flower has a creamy white color and has a measurement of 0.5 cm wide
  • Japanese knotweed flowers have a spikey feature that has an approximate length of 10 cm.

Japanese Knotweed Rhizome (Root) 

  • Japanese knotweed rhizome has an estimated diameter of a few mm up to 20cm
  • The physical appearance of the roots has a dark brown on the outside and yellow-orange on the inside
  • They are brittle like a carrot.

Herbicide Spray and Injection Effects on Japanese Knotweed 

Glyphosate herbicide is one of the most effective removal methods of Japanese knotweed. It can cause a massive amount of effects on its stem growth. Heart-shaped leave can prevent from growing into short and tiny leaves or commonly known as “bonsai” growth.