It looks quite like Mirabilis jalapa - if you've had it a while, it must be the tuberous kind, although people often grow it as an annual, ripping it out when autumn arrives.

I also think it is Mirabilis. a nice specimen and lucky to keep it going for so long.

Yes, agree with the others, and it's grown amazingly well. It is white Mirabilis (also known as the 4 o'clock flower, as that is usually when the flowers come out). The 'other' Mirabilis has red, yellow and pink flowers all on the same plant!

Thanks,it's not a favourite but it does add a bit of late interest in the boarder.