What does Japanese knotweed look like? The six key characteristics you should know

Timelapse shows alarming rate Japanese Knotweed grows at

We use your sign-up to provide content in ways you’ve consented to and to improve our understanding of you. This may include adverts from us and 3rd parties based on our understanding. You can unsubscribe at any time. More info

Japanese knotweed is renowned for its rapid growth and astonishing ability to spread quickly throughout Britain. Being able to identify this notoriously invasive plant is crucial to prevent costly damage to your property – especially in winter when it can appear dormant in your garden. With even the smallest amount of this nuisance weed taking years to get under control, catching it early is your safest bet – but what should you be looking for?

Why is Japanese knotweed a problem?

Japanese knotweed has built quite a reputation, having been found to withstand harsh weed killers and cause severe damage to properties.

Earlier this year it was even revealed by the Independent that having Japanese knotweed on your premises could drive house prices down by as much as 10 percent.

In fact, this invasive weed poses such a threat to the stability of your home that mortgage lenders will often refuse a mortgage to people buying a property with live Japanese knotweed growing on the premises.

While it is not illegal to have this herbaceous perennial growing around your home, it could leave you severely out of pocket if it gets out of hand.

What does Japanese knotweed look like?

As the most widespread form of knotweed in the UK, it is likely that you have come across this destructive plant at some point in your life.

Though it typically blooms between late summer and early autumn, Japanese knotweed can be recognised by its unique foliage and bamboo-like stems.

One of the most concerning things about this property-invading plant is that it can easily be mistaken for common shrubs, such as dogweed, because of its voluminous foliage.

Identifying Japanese knotweed is easier than you might think when you know what to look for based on these six key characteristics:

  1. The flowers
  2. Height
  3. Foliage
  4. Stems
  5. Roots
  6. Seeds

What do Japanese knotweed flowers look like?

The flowers on this destructive weed can be deceiving with their delicate cream hue and fluffy appearance.

Japanese knotweed flowers are typically half a centimetre wide, grown in stemmed clusters which can grow up to 10cm tall.

Flowers are most prominent on this weed when they bloom in late August through to mid September.

How tall is Japanese knotweed?

This invasive weed can grow up to seven feet tall, though it has been known to grow even taller- reaching 9.8 feet in height.

Between late spring and early summer Japanese knotweed can grow as much as 10cm per day.

DON’T MISS:
Birds may give up long-distance migration – JOHN INGHAM [INSIGHT]
Japanese knotweed warning: Buyer ‘shocked’ after finding weed at home [NEWS]
Japanese knotweed: ‘Key’ signs you have invasive weeds in your garden [GUIDE]

What do Japanese knotweed leaves look like?

Perhaps one of the most confusing characteristics of this weed is the generic foliage.

Japanese knotweed leaves are often light green with a red or purple hue glazed over each leaf.

The leaves can be identified by their distinctive pointed heart shape which stem from the plant in a zigzag pattern.

As they mature, fresh leaves will appear rolled up with rich red lines running through them like veins and can grow up to 20cm long.

How to identify Japanese knotweed by its stem

The zigzag pattern is easy to spot in the stems of Japanese knotweed as they shoot off in a random formation.

Stems appear hollow green with purple and red flecks and can grow up to two or three metres tall.

Japanese knotweed stems can grow up to 2cm per day, making this nuisance weed hard to control as it spreads.

What do the roots of Japanese knotweed look like?

Known as rhizomes, the roots of this rapidly growing weed are responsible for the overall progression of the plant.

The outside of the roots appear dark while the inside has an orange/yellow hue.

These roots can grow three metres deep and between two and seven metres wide across the soil.

While the growth of the roots is determined by soil and weather conditions, Japanese knotweed roots are most commonly known to grow to around 20cm in diameter.

How to spot Japanese knotweed seeds

The small heart shaped seeds have distinctive wings though unlike most plants, Japanese knotweed rarely tends to grow from seed.

Instead, this herbaceous weed sprouts new growth from nodes or chunks of the stem in soil or water.

Source: Read Full Article