Are there aphids on your passion vine plant somewhere?

I am not seeing aphids on them, but there do seem to be these darker green nodes that the ants are interested in.

Those darker nodes are actual sugar like glands, nectaries, that attract the ants to protect the plant from the likes of caterpillars. From what I've read, ants are usually not a problem of any sort, unless you stick your nose in a bloom and it is covered with them, like I did last week, LOL. The aphids that hit buds usually burrow inside the buds and you don't see them however I haven't personally experience that problem with passiflora only hibiscus.

http://www.jstor.org/discover/10.2307/1938594?uid=3739600&uid=2129&uid=2&uid=70&uid=4&uid=3739256&sid=21103794922801

I actually heard something quite interesting about those extrafloral nectaries (as they're called in the botany world). They act as a defense against aphids. The theory is that the ants find the sugary nectar from the gland more attractive than the secretion from the aphids they farm on the vine, they then eat the aphids for the protein they provide. It is an interesting theory, and it sounds good, so it's what I'm going with for now.

Not the link I was looking for, but it works.

Here is a link that might be useful: Ants: Not always bad!

We have tons of ants this season too but not on my passion vines which are getting a slow start. I just put some Grant's Ants stakes out that I had in the cupboard. The neighbor has been having an issue in the house with them. And there are huge nests in the garden where they come pouring out like in a horror movie. Good luck with yours and hopefully whatever is going on will pass so you get your flowers.

Thanks everyone for the advice and links. The ants are still there, but the passion flowers are now blooming as they should, so all is well on my vines once again.

I don't generally kill ants outside, because I know they are beneficial. I have had indoor issues in the past (a river of them to my cat bowls) and in the end solved that one with ground up dry cat food mixed with boric acid.

I . . .