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Messages are welcome on any subject relating to Troopers Hill Local Nature Reserve; the surrounding area of St George and Crews Hole or any of Bristol's Parks and Green Spaces.


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Viewing Page 1 of 1 (Total Posts: 6)


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Helliott

BS5


Oct 13, 08 - 12:22 PM
Fiends of Japanese Knotweed

BBC news story about natural predators for Japanese knotweed - a sap-sucking psyllid insect and a leaf spot fungus.



http://news.bbc.co.uk/1/hi/sci/tech/7531221.stm
Liz



Oct 15th, 2008 - 10:07 PM
Re: Fiends of Japanese Knotweed

I heard that on the radio this morning & wondered what the sap sucker would eat when it's eaten the knot weed. It doesn't seem quite right to import something else to sort out a problem caused by an imported plant.

Liz
Susan

BS5


Oct 15th, 2008 - 10:44 PM
Re: Fiends of Japanese Knotweed

Liz, I can quite appreciate your concern, however there are some good success stories about biological controls. For example ragwort, that quite pretty weed that kills off horses by damaging their livers, has apparently been quite successfully controlled in North West America by the introduction of our native cinnabar moth and the ragwort flea beetle. Now I read this on the internet which I know is not a 100% reliable source on all occasions but I was aware that the cinnabar moth had been introduced to New Zealand in the 1930s for the same purpose and although it did not wipe out ragwort it did do a fair amount of ragwort munching and did not cause problems elsewhere.

If sufficiently thorough testing has been done then it would be great if Japanese knotweed can be munched or moulded into submission rather than millions of pounds having to be spent controlling the stuff with a very specific herbicide. Japanese knotweed wipes out lots of other plants by shading them out during its lifecycle where it grows to over 7ft and then dies back in the winter, leaving its roots ready to spring into action and spread further in the spring. In its dormant phase it leaves bare slopes in winter causing considerable erosion.0.8g of root is enough to generate a plant. Roots run for over 60 feet and snap off very easily.

I personally would be very pleased if Bristol Parks no longer had to go through the lengthy and expensive process that they have had to do in a number of green spaces, including Troopers Hill, to control Japanese Knotweed.

End of rabbit - that's a thought - I wonder whether rabbits like Japanese knotweed? Let's introduce rabbits to Troopers Hill to find out - Lapin farci au mauvaises herbes de Japon, anyone?

All the best,

Susan
Jules

BS4


Nov 26th, 2008 - 9:45 PM
Re: Fiends of Japanese Knotweed

Here's another couple of biological controls:

Japanese knotweed is a wild edible.
Young shoots up to one foot in height can be harvested early in the spring, then steamed or boiled for four to five minutes and served like asparagus.
From the University of Connecticut web-site.
(Wonder if you can micro-wave?)

Wine.
Ingredients

Four Pounds (2 kg) of knotweed stems, leaves cut off and cut into chunks.
Three pounds (1.5kg) sugar
1 tsp yeast nutrient
Juice of one orange
Wine yeast (all purpose will do, but champagne yeast would probably work
very well).
Enough water to make up to 1 gallon (4.5l)

Put the knotweed into a straining bag, and put that into a sterilised bucket.
Get the water, sugar, orange juice and yeast nutrient to the boil and pour onto the knotweed. Let it stand, covered, till cool, and add the activated yeast. Keep it in the covered bucket for around a week, till the fermentation dies down a little, and decant into a demi-jon.
Treat as for other wines from this point, but if you manage to retain a vibrant pink colour then don't stabilise when bottling as the sulphite makes the colour
vanish.
Liz



Nov 26th, 2008 - 10:56 PM
Re: Fiends of Japanese Knotweed

Heck, we don't even harvest the apples and plums. Are we really ready to eat the knotweed? I wouldn't worry about microwaving. I boil asparagus for about 10 mins lying on its side in the frying pan. Not as much fun as those expensive pans to boil it standing up, but it works. I can't see knotweed would be any different.
These people haven't got to the unfashionable burbs of East Bristol yet, and they don't seem to know about knotweed. Maybe we can get them to try the wine recipe

I've got a very nice recipe for snails in a bourgignonne sauce if anyone's interested.
Jules

BS4


Nov 27th, 2008 - 5:40 PM
Re: Fiends of Japanese Knotweed

I eat the occasional bramble (one only needs 5 per day apparently) and plum, though the plums at Callington are sweeter. (sorry!)


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