do i need to cut back my cup and saucer plant back or leave it

The Cobaea is only hardy to about 7oC, well above frost levels Allie. I assume it is outdoors in which case (being tropical) it is grown as an annual in the UK. If it is outside it won't come back no matter what you do. If it flowered did you take any seed? If so you need to start it again. I just planted mine so too late to offer some. Sorry.

I think either Treesandthings or Andrewr (not sure which) also grow these so may have something to add.

John.

Hi Allie, I grew these this year for the first time. I have cut one down and composted it, the other I have left to see what happens. (probably nothing but I like trying different things) I shall definately be growing some more but I will have to get some new seed.

Good luck.