Japanese Knotweed

[robtandersen]

Hello, all you horticulturalists. We've avoided the Giant Hogweed but now there's this a scary invasive plant that has shown up in my yard near the river in Hubbard Farms. Haven't heard much about it in the press, this board, etc. Anyone else infected?

http://www.secondwavemedia.com/south...-own-0218.aspx

[Bigb23]

If you see it in your yard, approach with extreme caution. It's the Incredible Hulk of plants. Whatever you do, don't make it angry.

​
Am armed with flares and candles. Damn you Marvel Universe.

Attachment 36570

[RO_Resident]

We the plant on some property we used to own. The plant is insidious--over the course of a few years it went from a few plants to taking over a hedge and a flower bed. It would even sprout in cracks in the foundation of the house.

Didn't realize how bad it was until the DNR highlighted it in one of their invasives campaigns.

[robtandersen]

So I guess you sold the property to rid yourself of the plant...?

[RO_Resident]

No. It was my mom's house. We sold the property after she passed.

She loved gardening. As she slowed down in her last few years of life, she actively maintained a smaller and smaller portion of her flower beds.

The portions she left fallow filled with the Japanese knotwood. The dusty green leaves and red shoots are pretty distinctive.

It was only a couple years after the property was sold did we put 2 + 2 together and realize how bad the infestation was.

[Honky Tonk]

Once, in my younger days, I bought an ounce off of a guy. After getting it home, I realized it was definitely knotweed.

[jcole]

Once, in my younger days, I bought an ounce off of a guy. After getting it home, I realized it was definitely knotweed.

Oregano, huh?

[Dan Wesson]

Once, in my younger days, I bought an ounce off of a guy. After getting it home, I realized it was definitely knotweed.

[Detroitnerd]

I've had it before. Don't believe all the hype about "invasives." What we do is, we neglect land -- mistreat it, abandon it, pollute it -- and then blame the plants that grow there for "invading" the land. A balanced piece of land brimming with biodiversity will not easily yield to so-called invasive plants.That said, special care has to be taken to eliminate knotweed. It is allelopathic -- that is to say, it produces chemicals that retard the growth of other plants. Also, it seems to be able to grow from one section of root, so it's not best to start chopping away at it with a hoe.The best way to treat an area where Japanese knotweed has taken hold is to dig a trench around it and cover the entire area with a thick tarp. I did this once in my backyard garden I even used cinderblocks to anchor the tarp deep in the trench, to create a rhizome barrier that the roots couldn't get through. It's a tough plant. After more than a year of covering it, I realized some of it had actually survived under the alley slab, poking up between a crack, and another part had found refuge in an old garage, growing leggy branches in the thin sunlight. In the end, I won, but it was a big job.Since then, I've wondered if it might not be crowded out by natural rhizome barriers, like hostas, comfrey, or daylilies or other really tough plants that refuse to let other plants through. Then again, it's hard to win against allelopathy.It's my understanding that in Asia, there are natural predators who eat the plant. It is supposed to be edible: Maybe WE should try eating it. I've also seen some gardeners who are happy to leave a stand of it, as it can provide a bit of refuge for pheasants or other wildlife. Then again, some gardeners think that's just batty.

[Dumpling]

Thank you for this. I did knot now about this invasive before
you posted.

The current weeds: creeping charlie, burdock, mulberry, Canadian
thistle, bindweed, one or two similar small vines, morning glory [[but so pretty!), Rose of Sharon [[it is easy to deal with and pretty too), wild
grapes vines, the new invasive replacement elm, Ailanthus, regular
thistle....leaving out a few no doubt. Dandelions don't count in my
book - those are so susceptible to Scotts Step Two.

Oh yeah. Garlic Mustard just showed up a year ago behind the garage.

[jcole]

Don't forget purple lustrife; pretty but chokes out wetland quickly. And Russian Olive trees. They were not here before the 70's

Thank you for this. I did knot now about this invasive before
you posted.

The current weeds: creeping charlie, burdock, mulberry, Canadian
thistle, bindweed, one or two similar small vines, morning glory [[but so pretty!), Rose of Sharon [[it is easy to deal with and pretty too), wild
grapes vines, the new invasive replacement elm, Ailanthus, regular
thistle....leaving out a few no doubt. Dandelions don't count in my
book - those are so susceptible to Scotts Step Two.

Oh yeah. Garlic Mustard just showed up a year ago behind the garage.

[Funaho]

I always wondered what this crap was. I wish I'd known about not mowing it before now because it's slowly taken over a strip of my back yard.

[goggomobil]

Don't forget purple lustrife; pretty but chokes out wetland quickly. And Russian Olive trees. They were not here before the 70's

Russian Olive was brought here in the late 1800s as a hardy, quick-growing windbreak for farms.
Purple loosestrife was here in the early 1800s and is thought to have stowed away in European ships' ballast.

[robtandersen]

Thanks for all the info!