Don't want to give the wrong impression, myself (there are far better poisons). However, I'm a big fan of toxic plants (all `wimpy' ornamentals are scarfed up by deer here). When I wikied the 1080 I ran into some potentially useful plants...
"Sodium fluoroacetate occurs naturally in at least 40 plants in Australia, Brazil and Africa. It was first identified as the poison of poison leaf Dichapentalum cymosum by Marais in 1944,[3][4] although it had been reported as early as 1904 that colonists in Sierra Leone used extracts of Chailletia toxicaria which also contains fluoroacetic acid or its salts to poison rats.[5][6] It is believed that the compound is even present in tea leaves in tiny amounts.[7] The Australian pea family Gastrolobium (poison peas), have sodium fluoroacetate in the leaf tips and seeds. This forces livestock farmers in Western Australia to hand-weed out all the plants from their paddocks. It also means that some Western Australian herbivores have, by natural selection, developed partial immunity to the effects of fluoroacetate; this has been used for an advantage in DECs wildlife conservation project named Western Shield."
So, thanks for posting TT!
Add some more inedible flora to the already existing mix of Castor Beans, Wisterias, Daturas, etc.