By Arleen
United Kingdom 
Should I be worried having planted an oleanda in the south facing border very close to the footings of my house, the plant has been there six years and is four foot tall and doing very well? From Arleen Edge, Dereham, Norfolk
2 Aug, 2016
Answers
The contention seems to be that they develop quite large roots but not being totally hardy they would need to be near the house or other sheltered spot. There are 2 options as far as I can see. One, dig it up with as large a rootball as possible and move it to another sheltered spot or large pot. Secondly, dig down along your foundations and install some rootguard material.
2 Aug, 2016
All parts of the Oleander are toxic to animals and humans and even honey made from the flowers is poisonous but as its been there for six years with no problems, I wouldn't worry.
2 Aug, 2016
You are lucky t still have it - must be the house wall that protects it in winter.
I believe they are moisture hungry though - found this link for you
http://forums.gardenweb.com/discussions/2157646/where-to-plant-oleanders
2 Aug, 2016