Monday, January 05, 2009
Killing Poison Ivy -- 1945
Click beetle on poison ivy, Presumpscot River, Westbrook, Maine.
From our friend Alfred C. Hottes' 1001 Garden Questions Answered (1945):
How do I kill poison ivy? -- A.C.F., Framingham, Mass.
"One pound of calcium chlorate in one gallon of water, employed as a spray, does indeed seem to be quite effective against poison ivy. It also kills other grasses and plant materials with which it comes in contact.
Sometimes sodium arsenate is used for the same purpose. Sodium arsenate, however, is a very active poison and it renders the soil sterile for a considerable length of time after it is used. Sodium chlorate is sometimes employed, but the fire hazard is so great with sodium chlorate that I would prefer to use calcium arsenate, even though the chemical is not quite as effective.
Any clothing saturated by the chlorates or any of the wooden portions of spray equipment or anything of that sort, even the dead weeds and grass on which this material may remain, is a potential fire hazard. It is almost like gunpowder. Cases have been known of fires starting as a result of animals running across treated weed patches. But this hazard does not last long, as it is only a question of a short time until the material is all gone through the action of rain, etc. Small patches of poison ivy can be killed by covering them with tarred or other heavy paper that completely excludes light.
The most rapid and surest way to deal with poison ivy is to pull and grub it out down to the last inch of underground runner, but if you're susceptible to poisoning, don't attempt this method. Pull and grub clear to the end of each prolonged underground runner. Burn all pieces. But don't forget the laundry soap after each battle."