Ponytail Tree - Should I remove dead flower after it's finished flowering?

Hi

I would like some advice about my Ponytail Tree which has just finished flowering. We purchased it six months ago to adorn a very large pot (chest high). We were advised these plants only flower every ten years, but we must've been in luck because it produced one stunning flower almost as long as the trunk of the tree itself during the summer months. The flower has now died off but the very large, thick stem remains. Should I remove this at the base of the stem or just let it die off further and possibly fall off. I don't want any of the plant's nutrients to be diverted into feeding the flower now that it has dropped all it's seeds.

Thanks - Kate

 

Cut it off once there are signs that the flower stalk is beginning to dry up.

 

Thanks for the advice Mark - sorry it's taken me so long to get back on-line - but very much appreciated - Kate