Passion flower – getting buds to bloom


My Passion flower vine has many buds but very few actually open up although when one does it’s gorgeous! We’ve had the vine for several years and have been successful in overwintering indoors and summering outside. We’ll see multiple buds but few actually open. Please help! Thank you


Hello and thank you for your question. Passiflora, known also as passion flowers or passion vines, is a genus of about 550 species of flowering plants in the family Passifloraceae, The vast majority of Passiflora are found in Mexico, Central and South America, although there are additional species in the United States, Southeast Asia and Oceania. Some species of Passiflora have been naturalized beyond their native ranges. For example, the blue passion flower (P. caerulea) now grows wild in Spain. The purple passionfruit (P. edulis) and its yellow relative flavicarpa have been introduced in many tropical regions as commercial crops. P. edulis is the species most commonly found for sale in Toronto. It will eventually produce a fruit that becomes purple when ripe.

I searched for quite a while for some academic sites on growing this vine, but couldn’t find anything. Neither could I find anything but fairly general advice about blooming. Everything I read had these same 4 categories that I’ve listed first below.

1. Age of the Plant – Passion flowers need several years to become established and bloom. Your plant seems to be old enough because it produces flowers, but not many open.

2. Fertilizer: Passion flowers, at their core, still more wild than domesticated. They don’t need to be pampered. Nitrogen feedings, especially, may result in fast, spindly vegetative growth at the expense of flowers. The addition of phosphorus, like bone meal, can usually help offset this. Like many other native plants, passion flower thrives on a bit of neglect.

3. Lighting: Fruiting plants need as much sun as they can get, and passion flower is no exception. Even if you never intend to harvest them, your passion flower is hard-wired to turn those flowers you seek into fruit, and this means being able to create lots of food with the help of the sun. Check your passion flower during the day to make sure it gets at least eight hours of direct sunlight; otherwise, it may never bloom or bloom only sparsely when it tries. Passion flowers like a little shade in the late afternoon if the temperatures climb above 35 deg C

4. Watering: Passion flowers are tough enough to handle drought conditions, but grow best when planted in a well-draining location and watered frequently. The soil should be moist, not wet.

5. Bloom Period: Here in our southern Ontario climate, passion flowers bloom from July to September.

This article has some interesting information.

I have 3 different species of passion flowers myself. One never produced flowers but the other 2 did. I used to keep mine inside in the winter and then put them out on the patio in the summer. They got full sun for 5-6 hours per day. In the years I’ve had them, I’ve got a few fruits but they didn’t fully ripen. This year, I have left them in my sunroom. It’s bright there and I’ve moved them as close to the windows as I can, but I doubt they will bloom as they get only a few hours of direct sun. They grow to be a big vine and I found them difficult to move in and out. Last year, outside, I got fewer flowers than usual and that may have been because I fertilized them too much.

I love passion flowers and your question encouraged me to look for a book on them. I found only one on Amazon and ordered it. Hopefully, I’ll have more to say on passion flowers later in the summer.