Passiflora Caerulea

Short version:

I chose this passion flower because it was frost hardy perennial climber that grew in some shade, was evergreen and provided edible fruit. It has done brilliantly in my garden and has amazing flowers followed by orange, egg shaped fruit. 

Passiflora / passion flowers are gorgeous as both a plant and a flower. The whole structure with its many dangling vines can transform a bare surface, whilst the individual flowers look incredibly exotic. There are many passion flowers of varying colours – but you may have noticed, I’m only interested if a plant is edible. I’m therefore, only talking about passiflora caerulea because it ticks all of my boxes.

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Flowers

I really think they are stunning. It has a long flowering season. It can begin flowering (here in London) in late May and can continue till September. This will depend on the weather from year to year. The bees love them, and I often see them buzzing around the vines. This is of course also important for pollination so that the flowers will set fruit.

Fruit

Of course, it would be wonderful to grow passiflora edulis as these are the passion fruit that we recognise from the shops. Unfortunately, these wouldn’t survive the winter outdoors (I have neither the space nor the patience for greenhouse growing) and it certainly wouldn’t be warm enough in the UK alfresco for the fruits to fully develop. The caerulea is a decent substitution. The fruits are a gorgeous orange colour with a size and shape similar to a hen’s egg. These are edible – WHEN RIPE. When not ripe enough the fruit can cause tummy troubles. The fruit does need a good summer to ripen. A word of warning though – only the pulpy seeds are edible. The rest of the fruit should be discarded and the rest if the plant is also toxic. If this sounds worrying then to put your mind at ease – or maybe give food for thought – potato leaves are also toxic. Potatoes, along with tomatoes and aubergines are part of the nightshade family and none of the leaves of those plants should be eaten either. With any unusual edibles it’s a good idea to do your own research and read websites that you trust for information. I think that the Royal Horticultural Society is a good resource.

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Taste is also important. I won’t lie. They don’t taste much like the passion fruit we’re used to – but it tastes OK. Nothing amazing, but pleasant enough.

Vertical gardening

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It uses tendrils to climb up anything that will support it. In my garden it climbs the blackberries and the grape vine. It’s woven itself though the blackberry bushes and has resurfaced again about 4m away from the original plant. 

The tendrils are great because this is not a plant that will damage brickwork, unlike ivy – which tunnels roots into mortar and is impossible to remove. I did mistakenly allow ivy to climb up a house once because I thought it was beautiful. When we came to move, I spent about 10 hours trying to remove the ivy. I yanked, scraped, scrubbed and brushed, but you could still see the debris of tiny roots entrenched in all available pores.

The climbing also means that it takes up a small footprint, which is a bonus for small gardens. You could have it scramble over a bike shed or to add colour and interest to a fence or wall.

Hardy perennial in British weather

The different varieties of passiflora vary in how hardy they are. Caerulea will survive outdoors fine and ours didn’t seem to be bothered by frost. In our garden in London it can be evergreen. It is deciduous to evergreen depending on how warm the local area is. Being evergreen means that it has made a great living screen by our fence. It has hopefully given our neighbours some protection from my child’s mooning (yes, that’s not a typo – but she is only 3 – and getting naked on private property seems to be her thing) and screaming (something else I think is also connected to being 3).  

It also seems to do fine in shade. Its roots and the first 4 feet of the plant spends most of the time in shade. If you’re looking for edible fruit though, you’ll want it to grow in decent amounts of sun.

It returns year after year, despite freezing conditions. It does follow the adage: first year sleep, second year creep, third year leap – or it did for me anyway. First year it was a sorry looking thing with a few scraggly vines. The second year it provided a bit of privacy and one orange fruit.

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This being the third year it covers a good 2 square metres or so. It has wonderfully flexible vines so I could weave it in and out of the frame however I liked. It also has about 20 or so fruit which are now all turning orange. With our current blackberry canes going mental and a grape vine in the middle, it is a little difficult to see where one plant ends and the other begins.

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Doesn’t need looking after

In South Africa it counts as an invasive species that takes over indigenous plant life. I haven’t read anything that makes this plant a cause for concern in the UK. It doesn’t propagate particularly easily here, and I have never seen it anywhere in the wild. This does mean that it grows brilliantly, even with plenty of neglect. I’ve read that it in fact does best when allowed to get a little unruly and not kept too neat. They do grow to be quite large plants, though some patience is required in early years. When the plant is in its first couple of years and doesn’t look like much, don’t be tempted to fill in the space (like I did – doh!) with other perennials. If you want something vertical you could grow some peas, beans or maybe a cucamelon or another annual to fill in the gaps because this passiflora really will fill out.

It’s vigorous enough to cover a surface – but not so overly aggressive, like ivy, that you’ll continuously need to hack half of it down just to keep it in check. It’s easy enough to remove whole vines if you do need to keep it small. Pinching out the growing tips of the vines can help it to branch more.  

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If you’re looking to grow something that tastes amazing, I’m afraid this probably isn’t it. I’ve decided that there are still plenty of other reasons to grow these and I’ll continue to do so until I decide I need the real estate for something else. That something else is going to have to have all the bonuses of climbing, being hardy, being evergreen, be able to thrive on neglect, be bee friendly, be beautiful and then taste pretty wicked in order to trump passiflora caerulea.