We recently planted a Passiflora Lavender Lady vine in the ground and it's growing quickly up a trellis against a fence; but is there a way to encourage it to create more branches to fill out to become more full looking?
It will branch out more over time, but these plants tend to only put up a few stems from ground level, go straight up, produce lateral growths and then those tend to spread outwards or dangle downwards. If you want flowers this year, don't cut it now, but you can cut it right down to about 6 inches in mid to late winter if it doesn't die back to ground level to try to encourage more shoots from the base. Don't prune any later than that because this one flowers on growth it makes the same year. Further info here https://www.gardenia.net/plant/passiflora-lavender-lady-passion-flower#:~:text=Propagate%20by%20seed%2C%20semi-hardwood,the%20longer%20shoots%20as%20necessary.