Hi Diane,
It's not unusual for the blooms on many passies to only last a day. I'm in zone 7a and winter my passies over inside. I used to cut them way back when I brought them in but did keep them in a warm, light room and watered them infrequently. They weren't completely dormant and would put out some growth but not much. Not like my brugs or plumeria. I started using HID lights for over wintering my plants and now I cut them back just enough to get them in the house. They continue to grow and bloom well over the winter under the HID lights. I just have to cut them back enough to get them back outside in the spring. I allow them to dry out between waterings and don't feed them much at all. I do dig some chopped banana peels into the soil every 4-6 weeks during the time they are outside.
Karyn

Don't worry about shocking them. Since I keep most of mine in pots, I overwinter several in the garage with only a few windows. They won't go dormant totally. My belotti vines kept flowering all winter even with little light. Most of the others quit flowering though. I set my pots up against a fence where they can climb during the growing season and chop them down to a manageable size for winter storage. They dont act like they care at all. Nice to see you over here (from the brug forum lol).
~SJN

I'd think the conninea would be more susceptible to shock than the caerulea. As a rule of thumb, the red passiflora are generally not very cold-hardy. Cut it back, but don't get draconian.

With the caerulea, I wouldn't worry much about shock. Caerulea is one of the hardier plants when it comes to cold, and will retain its leaves even when temps drop down to 25 degrees F, and regrow from the roots at colder temps that kill the vine to the ground. However, I don't know if they're hardy enough for your Colorado climate, so if you plant one in the ground, I'd err on the safe side by taking cuttings as well.

What is the best way to take a cutting from a passion vine planted in the ground, and when would be the best time to do it. Thanks in advance.

Thanks for advice and info. My vines are growing along a deck railing that has deer fencing stapled to it (plastic mesh of 2" squares) so it will be all a jumble by the time it gets cold. I'll have to cut back quite a bit. The red vine is growing more slowly than the blue, and has produced only one flower so far. The blue is going nuts. They both tend to dry out daily and get watered daily. I think they're in 2 gallon pots, although I don't know nursery sizes for sure. We get to 20 below freezing here sometimes in winter so there's no way I can leave them out. Probably will go in a basement room for winter without artificial lights, but the room is pretty light from a corner window. Those brugs just get shoved in a dark corner and mostly ignored till March.