Compost: don't include triffid in the mix!

This is a cautionary compost tale. In theory almost everything of plant extraction should be possible to compost. But not Parrot's Feather Myriophyllum.

I cleared a lot out of the pond last summer as it tends to overwhelm the surface and cause the aquatic oxygenaters to die back. I mixed it in with chicken straw and grass as the bottom layer of the new heap I was making, thinking that a year underneath a hundred-weight of hot, actively steaming muck would kill it off. Wrong. When I came to harvest this heap earlier in the summer, the bottom layer was still full of wiry, strongly-rooted stems that looked far from dead. It was impossible to use in this state, so I left it. Within a week, the stems had started to grow and produce fresh green leaves. This plant does not need water, it can grow in fairly dry soil like any other. It is truly a pest. I have now treated with glyphosate, which has wilted it a little, but I'm still not sure that I can just compost over it again. I think I'll have to dig it out and destroy some other way.