I have Hydnora Africana roots underneth my house, it is lifthing the floors the extent that doors are unable to close and walls crack with 20mm gaps as the roots lifts up the structure. How can this plant be killed off to stop re-growth of this plant roots causing damaging affects?
This plant is, actually, parasitic! The host species is what is causing all of your damage. Likely, this is a species of Euphorbia, but there are many that this parasitic plant will attach to. This article will explain:
Killing of the host tree can be done with some persistence. This article will help: