According to Better Homes and Gardens, "The best time to prune a passionfruit vine is in late winter or early spring. Cutting the vine back by about a third will encourage vigorous growth and more fruit." However, according to gardeningknowhow.com, "Trimming passion vines lightly at any time of the year is acceptable to keep growth in check but may result in the removal of some of the season’s buds." It's completely up to you. Personally, I probably wouldn't prune them now, in September, for fear of having a smaller harvest next year. However, to help you make up your mind, the best article may be at gardeningknowhow.com. Good luck.
Answers & Comments
According to Better Homes and Gardens, "The best time to prune a passionfruit vine is in late winter or early spring. Cutting the vine back by about a third will encourage vigorous growth and more fruit." However, according to gardeningknowhow.com, "Trimming passion vines lightly at any time of the year is acceptable to keep growth in check but may result in the removal of some of the season’s buds." It's completely up to you. Personally, I probably wouldn't prune them now, in September, for fear of having a smaller harvest next year. However, to help you make up your mind, the best article may be at gardeningknowhow.com. Good luck.