Weed control is a major problem at NRC.
I'm not sure how many species of noxious weed grow on our property. I'd guess it is a few dozen but I would not be surprised if it was more.
I'll only mention to two which are topical at the moment and add others later.
This vine is a big problem for us. It has been killing our mature sheoaks.
Controlling it by cutting and applying herbicide is very labor intensive.
The majority of the vine grows close to the creek where there is a real risk of water contamination. Round-up and frogs should not be mixed.
Alan published his control method here
Last year (2007) two biological control agent were released from quarantine after years of research.
My Biological control page is here
All the properties in along the creek received weed notices about thorn tree in late 2007.
We've since had an a large number of thorn trees poisoned by contractors.
We don't have the time to do it ourselves and trying to do it without chemicals is pretty much out of the question.