I had two passifloras, beautiful flowers, spectacular but very intrusive and also poisonous.  I made the mistake of putting one small plant in my greenhouse, I had seen one at the Cambridge botanic garden inside, and I liked the look of it.
It completely took over the greenhouse and was very difficult to get rid of.  A very small piece of root is sufficient for another plant to grow.  I dug out as much as possible and keep pulling out any new growth.