Does anyone know what this plant is??

Hi all, 

We’ve had this plant in our ‘garden’ now for a few years. It doesn’t like a lot of water!! We’ve learnt that if we give it too much water, it’s leaves brown and fall off. I’ve cut it back a few times, then it shoots back up , when we go back to the UK for a month or two.

We have not been here for 9 months , so it’s had time to grow, roughly about 5 foot!!!!!

We’ve never seen it flower, and can’t match it’s leaves in garden centres???!!!

What is it???

Regards