Q.dipladenia
I kept my dipladenia plant in the house over the winter and then when it got warm I put it outside. It looks really good but I wonder if I should cut it back. It has quite a few long vines and I don’t know if it flowers on new growth or if it will flower on the old part. Thank you for any help you can give me. Don’t know if I spelled the name right but it is like the Mandevilla plant. Thanks again. Ellen

You certainly can pinch back or trim the plant to encourage more compact growth.
https://www.gardeningknowhow.com/ornamental/vines/mandevilla/growing-a-dipladenia.htm