Advertisement Just a little info bit on plant control, especially for those living in the Pacific Northwest. (Land of the Himalayan Blackberry) I wanted a chemical that presents no systemic toxins to animals. I also wanted something that if you spilled a few hundred pounds/gallons among your rose bushes it would meekly decompose and at worst, change the pH a little. Doing a little research, plagiarizing info from various authorities at arboretums, I came up with a weird little plan. Some plants are decidedly acidic. They get alkali into their system they wither and die. Just check the various alkali flats and their abundant lack of vegetation. So barring dumping sodium hydroxide all over vast areas the question was how to get alkali into the plants and what alkali. Solution was a solution. Simple and elegant. The 'poison' of choice, Na2CO3, washing soda, sodium carbonate. pH of 11.5. Next I needed to make a solution of the stuff wet so it really sticks to the plant. The leaves. Which are basically what? Cellulose. What common crud found around the house wets cellulose? Laundry detergent. That is how it works. It's big job. The formula I came up with, which can vary, was 1/4 pound Sodium Carbonate + 1 teaspoon generic laundry detergent in one to two gallons of water. The liquid should feel slightly slimy, but only slightly. You're not trying to wash clothes here. Next I had to convince the plants to eat the stuff. Simple. Spray it on the leaves, getting them good and wet, preferably late in the afternoon. It sits on the leaves all night then come dawn when plants go through their transition phase, they take their last gulp of dew from the leaves. The more sensitive to pH, the more effective the glurp is. Poison Oak and friends, Rhus family, are very susceptible. Likewise, Himalayan blackberry. As an added bonus, if you get the stuff on your favorite pet plants, just give them a thorough rinsing with clear water. Effect. Done right in 24 hours the victim plant will look like it just weathered a forest fire and didn't win. Severe die off from lack of photosynthesis occurs. When the plant starts regrowth the young leaves are even more susceptible to pH screwings. The root system eventually gives it up. Experiment. Precautions: Don't eat the stuff. You'll be burping and farting technicolor surround sound sub woofer enhanced thunder for a week. Keep out of eyes. Mild caustic. Will irritate skin. Sensitizer. Added precaution. Poison Oak is an environmentally beneficial plant that resists soil erosion. Think twice when trying to eradicate it on slopes that may be susceptible to erosion. Especially soils that contain a significant amount of sand or decomposed granite.