I trim mine when it starts getting cool. Taking the vine down about 1/4 height/width with each cutting until it is about 1/4 the original size/height. I spread that out over several weeks so that the plant does not have a freak out attack.

If you have out of control bits now, you can just trim those off and it should not bother the majority of the plant.

~Tiger

Jackie
Bearing in mind that you are growing in UK (much cooler than Dallas usually though 30C in London today!) this time of year is a good time to prune-when the plant is growing strongly. As Tiger says do a bit at a time though or the plant could go into shock. Don't worry re bark damage.
Myles

Thanks both of you for the advice, will do it very carefully, don't want to stress the plant.
Temperature here today is 28C, next week I guess we will be back to a normal British summer.....!
Jackie

i never did get used to the celsius/fahrenheit conversions!

what growing zone are you in the uk? lovely that you are able to overwinter you cerulae!

Passionflow:

Where can I buy Passion flowers to grow here? I'm very attracted to how it looks and want to give it a try. Any tips? Is now a good time to plant?