Oleander is a garden shrub or small tree that can be found all over the world. Recognizable by its bushy, colorful flowers, it's also extremely toxic and oft-considered a pest in gardens. Great care must be taken when killing and disposing of your oleander bush to ensure that you do not accidentally harm yourself.
Glyphosate is the main ingredient in many types of herbicides, including Roundup. Glyphosate inhibits the growth and metabolism of plants, effectively killing them. It is only effective on actively-growing plants, however, and will do nothing to prevent new oleander from cropping up after you've removed the old one. It is also not effective on large oleander trees, as it may kill some leaves but not the whole shrub. It is most effective on young oleander plants that are still under a foot tall and should be used in conjunction with cutting and digging.
Cutting and Digging
Cutting and digging is the most effectively way to kill an oleander in your yard and is your only option if you have a large shrub. This method involves literally cutting the oleander shrub down to its base and then using a shovel to dig up the plant's roots. The cut shrub should then be sealed in a heavy-duty bag for disposal. Glyphosate should be sprayed on the ground near the cuttings to kill off any roots or stubs you may have missed.
Always wear thick gardening gloves and a dust mask when dealing with oleander as it is extremely toxic not only to animals but to people. If any is accidentally ingested, it can cause adverse symptoms, including nausea and irregular heartbeat, and even death. Just a single leaf of oleander can be deadly to infants and dogs or cats if digested. The bags of discarded oleander should be sealed tightly and disposed of promptly so no animals can get into them. Never burn oleander as the fumes can be toxic.