Difficulty: Moderately Easy
Step1
Hammer a dozen or so copper nails into a tree. The nails will slowly kill the tree and help dissolve the grip of its roots. When it's finally dead, it will still involve some of the heavy tree removal, but felling the tree and eliminating the root system will be far easier. This is good for obstructions or root systems that are damaging structural foundations.
Step2
Lift the bark, bore a hole in the tree with a large drill bit and fill it with copper sulfate. This can be done in addition to the nails or a substitute.
Step3
Spray your plants with copper sulfate and bury it in the soil around a plant bed. The most immediate example where this would be effective is kudzu. You can yank it, mow it, cut it or burn it, but it never seems to go away. While copper sulfate occurs naturally in plants, overloading the plant will poison it. Think if we consumer large portions of nitrogen. At any rate, the copper sulfate does a great job of attacking the root structure. So, even the something like kudzu will come back, it will take much longer than if removed with other methods.
Step4
Spray large crops or beds of diseased plants with copper sulfate for removal purposes. Not only will it kill the plant, but it will kill the disease (spots, mildew and others). It will take care of large swaths of infected plant life at once, and prevent the disease from spreading.
Step5
If you wish to salvage the plants, but kill a disease, mix a small portion of copper sulfate with lime and water. Think one part copper sulfate, one part lime, 10 parts water. This small, diluted portion will not harm the plant, but will eliminate the disease.
Enthusiast 
