Knotweed
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ryansheehan
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15-20 years ago my guide on the Delaware talked about a program to cover the knotweed in plastic after being sprayed with something...obviously that didn't work.
If you have this on your land, you can cut it down regularly with a tractor and brush hog. It will be replaced with grasses. Knotweed can't tolerate regular mowing. You probably would only have to mow it about twice per year.
Then you can plant trees, and continue mowing around the trees until they get fairly tall, to keep the knotweed suppressed.
Once the trees get tall enough, they'll be fine.
This approach obviously wouldn't work for the thousands of acres along our larger rivers. But for a small property, it's an option.
Then you can plant trees, and continue mowing around the trees until they get fairly tall, to keep the knotweed suppressed.
Once the trees get tall enough, they'll be fine.
This approach obviously wouldn't work for the thousands of acres along our larger rivers. But for a small property, it's an option.
redietz
Well-known member
Relevant passage from an article in Slate:
"Hammer has found three changes in infested landscapes. First, knotweed grows so densely that virtually no sunlight hits the ground in a knotweed forest. In the massive Coos County patch, he said, there were no more than two other plant species growing in the knotweed’s shadow. That, in turn, reduces the number of bugs that might live in that landscape. Where there are fewer bugs there are fewer birds, and so on.
Second, and relatedly, new trees can’t grow in a knotweed monoculture, which is very bad for streams. In a native New England forest, dead branches play an indispensable role in shaping streams. Woody debris feeds bugs who feed trout. Logs create eddies and pools, which enhance stream habitats and provide places for sediment to collect, improving water quality downstream. Fewer trees, fewer pools, fewer bugs, fewer trout.
In knotweed colonies, Hammer also found that the ground was barren of organic material, which increased the likelihood of soil erosion during rainstorms. Sure enough, when Hammer looked at the boulders and cobbles in streambeds near knotweed growth, he found that rocks downstream from the plant were more likely to be coated in silt. That’s bad for fish and invertebrates who use the clean rocks for nesting, he said, and bad for humans whose water, down the line, may be carrying chemicals from fertilized soil that makes its way into the stream."
The whole article can be found at Slate article on knotweed
It's truly horrible stuff.
"Hammer has found three changes in infested landscapes. First, knotweed grows so densely that virtually no sunlight hits the ground in a knotweed forest. In the massive Coos County patch, he said, there were no more than two other plant species growing in the knotweed’s shadow. That, in turn, reduces the number of bugs that might live in that landscape. Where there are fewer bugs there are fewer birds, and so on.
Second, and relatedly, new trees can’t grow in a knotweed monoculture, which is very bad for streams. In a native New England forest, dead branches play an indispensable role in shaping streams. Woody debris feeds bugs who feed trout. Logs create eddies and pools, which enhance stream habitats and provide places for sediment to collect, improving water quality downstream. Fewer trees, fewer pools, fewer bugs, fewer trout.
In knotweed colonies, Hammer also found that the ground was barren of organic material, which increased the likelihood of soil erosion during rainstorms. Sure enough, when Hammer looked at the boulders and cobbles in streambeds near knotweed growth, he found that rocks downstream from the plant were more likely to be coated in silt. That’s bad for fish and invertebrates who use the clean rocks for nesting, he said, and bad for humans whose water, down the line, may be carrying chemicals from fertilized soil that makes its way into the stream."
The whole article can be found at Slate article on knotweed
It's truly horrible stuff.
salvelinus
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I read that the stuff grows from rhizomes that can be three or four feet deep in the ground. I doubt twice a year mowing would kill it.What kind of mower would go through it? Maybe a brushcutter. Stalks get as big around as your wrist.
I've seen one property owner on the Delaware that was cutting it down to the ground with a old style sickle. Saw him working one day in mid-may and then again in early June. I haven't been back up but I'll be interested to see if repeated cutting it down did keep it under control. I'll report what I see in September.
There are a couple of landowners I know along the Delaware that re-claimed their riverbank from knotweed. A couple of years of mowing twice per year and grass replaced it. Obviously it would be very hard to replicate this on steep stream banks.
Mark C
Mark C
One of the invasives I hate is the lesser celandine - it seems to have taken over the flood plain in most limestoners I fish. The yellow flowers look pretty in spring, but they pretty much crowd out all the native understory plants.
Invasives screw up things for a while. 20 years ago the big invasive along my local stream was purple loosestrife. An insect pest was found that knocked it way down, but then the flood plain area by me was taken over by stinging nettle, aka cow itch. I'm not sure which is worse.
A few years back I saw beavers cutting knotweed along the Willowemoc and I hoped for the best. Unfortunately, they didn't make a dent in the stand.
Invasives screw up things for a while. 20 years ago the big invasive along my local stream was purple loosestrife. An insect pest was found that knocked it way down, but then the flood plain area by me was taken over by stinging nettle, aka cow itch. I'm not sure which is worse.
A few years back I saw beavers cutting knotweed along the Willowemoc and I hoped for the best. Unfortunately, they didn't make a dent in the stand.
Baron
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The nettle is edible although it numbs the mouth. Its quite a thing in antiquity to have this for making rope.
My Mom planted the False Bamboo around our house in the 60's and guarded it for dear life. Didn't know then how this was going to turn out.
My Mom planted the False Bamboo around our house in the 60's and guarded it for dear life. Didn't know then how this was going to turn out.
The West Branch Susquehanna, like many other large rivers, has loads of Knotweed along it.
Just upstream from Lock Haven on the West Branch Susquehanna there are a bunch of riverfront houses.
They have lawns extending down to the river. Those lawns have grasses, not knotweed. Even though knotweed is thick everywhere else along there.
The reason is that those lawns are mowed regularly. Most broad-leafed plants cannot withstand regular mowing. That's because they depend on their leaves photosynthesizing to produce energy for the plant. No leaves, no energy, and the plant dies.
Grasses can tolerate regular mowing. And also some broad leafed plants that are adapted to low growth, so their leaves are near the ground and escape the mower. For example white clover.
As for the knotweed not attracting insects, tell that to all of the honey bees, and I mean lots, bumble bees, their relatives, as well as the ants and probably a number of other insects I missed in a cursory look at a stand of knotweed along Big Trout Ck near Slatington today. Some other insect had consumed portions of the leaves....possibly caterpillars like the large ones we found in ST stomachs from the W Br Schuylkill when we collected them for fish flesh contamination analyses. It was great to see all of those honey bees.
Stinging nettles are a native plant.
They are edible, but you want to cook them first! I wouldn't try eating them raw.
I've had cooked nettles and they were very good. They are very high in protein and when cooked in water they make a rich broth.
Nettles will burn you right through the common quick-dry nylon fishing pants that most flyfishers wear.
They don't burn you through blue jeans, though.
dryflyguy
Well-known member
Troutbert -
Can you compare the test of nettles to any other other green?
I've got lots of them - and knot weed - growing in the woods around my house.
And thinking about giving them a try
Can you compare the test of nettles to any other other green?
I've got lots of them - and knot weed - growing in the woods around my house.
And thinking about giving them a try
