Brugmansia

It won't kill it ... but it will have to grow to the point that it re-makes the Y before it will flower again.

When you cut it down last Autumn if you had rooted the cuttings they would be flowering-ready, without having to grow to form a Y, as they would have come from mature "flowering wood".

Wind the clock back, or jump in a time machine? !!

 

Thanks - will cut it back & see how it does. I didnt think of saving the cuttings last year, my problem tends to be that I leave everything to the last moment, particularly if the plants are still flowering & then have to rush to get them all put away - Must do better :-)