JAPANESE KNOTWEED (Fallopia japonica)
Indigenous to Japan,
knotweed was originally shipped westward by the German botanist Philipp von
Siebold.
When Siebold sent a variety of plant specimens to the Royal Botanical Gardens at Kew in August 1850, including Japanese Knotweed, he had no idea what he was unleashing on the world.
When Siebold sent a variety of plant specimens to the Royal Botanical Gardens at Kew in August 1850, including Japanese Knotweed, he had no idea what he was unleashing on the world.
With its beautiful heart shaped leaves, Japanese Knotweed has a pleasing appearance to the eye. It is what we can't see underground that is the problem. |
If you take a walk in
any local town, county or state park today you are likely to stroll past fields
of knotweed, especially near ponds, lakes and streams. All over Europe nations are on knotweed alert
including Latvia, Germany, Hungary, Austria and Switzerland.
Knotweed presents a pleasing appearance to the eye: heart-shaped
leaves, bamboo stems and pretty, little white-flower tassels in late summer and
autumn. What is less obvious is what lays below the ground .
The "crown" or "head" of a knotweed infestation can be the size of a bull's head, with scores of roots radiating out from it like strands of hair.
The "crown" or "head" of a knotweed infestation can be the size of a bull's head, with scores of roots radiating out from it like strands of hair.
In early spring knotweed's tender leaves are a food source for deer. In many cultures knotweed is eaten by humans. |
Due to its tireless and unstoppable army of unseen roots, knotweed
spreads outward forming clumps 65 feet wide and 7 foot high. Superficially resembling bamboo this plant has a
relentless killer instinct, overwhelming
native plants and forcing out wildlife. If you look through horticultural literature,
and you will see knotweed described as "thuggish,"
"ferocious," "invasive" and an "indestructible
scourge." The stems create
dense thickets impossible to walk though.
Amazingly there are very few male knotweed
plants in the wild. The females depend on their massive root systems to
propagate new plants.
In this photographs my dogs Ally (American Foxhound) and Lexie (Husky mix) lead me though a jungle of Japanese knotweed. This deer path would quickly disappear without its constant use by our local deer populations. |
Where it once it resided mainly in the wild, today it terrorizes
private gardens and homes, forcing its
way up through every crack imaginable, in patios, concrete paths, and even in
walls and floors.
If Japanese knotweed is spotted on your property action to
control and remove it should be taken immediately. What's more, getting rid of it is a task beyond
the average gardener. It can take up to
five years of regular chemical blitzing before the knotweed all-clear can be
sounded.
Uncontrolled knotweed infestations can negatively impact the
value of homes and property.
Knotweed is used around the world in herbal remedies and medications. It's negative effects on native plants and wildlife is now a major problem around the world. |
For more information contact your local cooperative extension or
go online to Penn State Extension: Knotweed.
Happy Gardening & Keep Keeping Safe,
James
*Thanks to Penn State University & Newsweek magazine for the
information in this article.