Passionflower in a Pot: A UK Container Guide

Yes, you can grow a passionflower in a pot, and it’s one of the easiest ways to bring an exotic-looking climber to a patio, courtyard or balcony. The blue passionflower (Passiflora caerulea) is tough, quick-growing and flowers from summer into autumn. The one thing to watch is winter. Roots in a pot get much colder than roots in the ground, so a little protection goes a long way.

This guide covers pot size, compost, support, feeding, pruning and keeping the roots safe in winter. If you have a border to plant into, the main guide to growing passionflower in the ground covers that instead.

Can you grow a passionflower in a pot?

Yes. Blue passionflower is the standard choice for UK pots because it is the hardiest and most vigorous. A little root restriction in a pot can even help flowering, as the plant puts less energy into endless leafy growth.

The challenge is cold. In the ground, soil insulates the roots. In a pot, the whole rootball can freeze in a hard frost. That shapes everything else, from the pot you choose to where it spends December. Get the winter right and a potted passionflower comes back year after year.

How big a pot does a passionflower need?

Start with a pot at least 30cm wide and deep. A young plant will fill it in its first season. Within a couple of years, move it up to a 40-45cm pot, which is about as big as most patios can handle.

Don’t jump straight to a huge pot. Lots of cold, wet compost round a small rootball can rot the roots, and a plant with endless root room tends to make leaves rather than flowers.

Weight matters too. A leafy passionflower on an obelisk catches the wind like a sail. A heavy terracotta or frost-proof glazed pot keeps it upright. A light plastic pot can stand inside a heavier one.

Each flower only lasts a day or so, but a healthy plant in a sunny spot keeps opening new ones from summer into autumn.

What compost suits a passionflower in a pot?

Use loam-based John Innes No.3, mixed with some horticultural grit, roughly four parts compost to one part grit. The loam holds nutrients and water well and adds weight. The grit keeps drainage free so roots never sit in water.

Mix the grit right through the compost and plant so the rootball sits a few centimetres below the rim, leaving room to water.

Multipurpose compost on its own is light, dries out fast and breaks down within a season or two. John Innes keeps its structure for years, which suits a long-lived plant.

Mix the grit through all the compost rather than putting a layer in the base. A piece of broken pot or mesh over the drainage hole stops compost washing out. Plant so the top of the rootball sits a few centimetres below the rim, leaving room to water. Each spring, scrape off the top few centimetres of old compost and replace it with fresh.

Where should a potted passionflower stand?

Stand the pot in full sun, ideally against a south or west-facing wall. The warmth from the wall means earlier, heavier flowering and a slightly milder spot in winter. In shade the plant grows leggy and flowers poorly.

Passionflowers climb with tendrils, so they need something thin to grip. An obelisk pushed into the pot is the neatest choice, and you can move the whole thing if needed. Against a wall, fix horizontal wires or trellis and tie in new stems as they grow. A sheltered corner out of cold north and east winds is best of all.

An obelisk in the pot gives the tendrils something to grab and keeps the plant portable, handy when it needs moving under cover for winter.

How to water and feed a passionflower in a pot

Water freely in summer and feed every two weeks from May. A passionflower in full growth is thirsty, and a pot against a hot wall may need watering every few days in summer and daily in a heatwave. Push a finger into the compost and water when the top few centimetres feel dry.

A pot in full sun dries out fast. Water at the base whenever the top few centimetres of compost feel dry.

Don’t overdo it, though. Roots sitting in soggy compost rot, and a plant that wilts in wet compost has usually drowned rather than dried out.

From May to September, give a high-potash feed such as tomato feed every two weeks. Potash encourages flowers. A general high-nitrogen feed gives you lots of leaves and few blooms.

How to prune a passionflower in a pot

Prune in early spring, before new growth starts. Passionflowers flower on the current year’s growth, so a spring cut doesn’t lose you any flowers. Cut the side shoots back to two or three buds from the main stems, and remove any dead or weak growth. This yearly trim keeps a vigorous climber in bounds.

Cut side shoots back to two or three buds in early spring. Flowers come on the new growth, so you won’t lose any.

In summer, just tie in new stems and shorten any that wander too far. Avoid hard pruning late in the season, as soft new growth won’t toughen up before winter. The guide to the best climbing plants has more climbers that suit pots and walls.

How to overwinter a passionflower in a pot

Protecting the roots is the most important winter job. Blue passionflower is fairly hardy in the ground, and in a hard winter its top growth may die back and regrow from the base. In a pot, though, the roots can freeze solid.

Here are your options, from safest to simplest:

1. Move it under cover. An unheated greenhouse, porch or garage with a window keeps the roots from freezing.
2. Move it against the house. A sheltered spot by a warm wall, out of wind, is much milder than the open garden.
3. Wrap the pot. If it must stay put, wrap the pot in hessian, fleece or bubble wrap, and stand it on pot feet so it drains.

Whatever you choose, keep the compost barely moist. Cold, wet compost kills more potted passionflowers than frost does. The guides to overwintering plants and protecting plants from frost cover wrapping and timing in more detail.

No greenhouse? Wrap the pot in bubble wrap and fleece and tuck it against a sheltered wall. Keep the compost on the dry side too.

Can you get passion fruit from a pot in the UK?

Sometimes, after a warm summer in a sunny, sheltered spot. Blue passionflower can set egg-shaped fruits that ripen from green to orange. They are edible when fully ripe, but bland and full of seeds, nothing like shop-bought passion fruit. Only eat fruit that is fully ripe.

After a warm summer, blue passionflower can ripen orange fruits. They’re edible when fully ripe, but bland and seedy.

Bees and other insects usually pollinate the flowers. In a cool summer, moving pollen from flower to flower with a soft paintbrush may help.

For tasty fruit, grow Passiflora edulis in a pot under glass. It’s tender and needs a frost-free greenhouse or conservatory, much like mandevilla, another tender climber.

Which passionflowers grow best in pots?

Passiflora caerulea, the blue passionflower, is the most reliable choice for growing outside. ‘Constance Elliott’ is a pretty ivory-white form, similar in toughness, and it looks lovely against dark brick. Passiflora edulis is the one for proper passion fruit, but only under glass.

Start with the blue passionflower if this is your first try. It’s forgiving and flowers well even in an average summer.

Common mistakes with potted passionflowers

• Too much shade. Without full sun, you get leaves and few flowers.
• The wrong feed. High-nitrogen feeds push leaves. Use tomato feed.
• A pot that’s far too big. Cold, wet compost and lots of leaf. Move up a size at a time.
• Soggy winter compost. It rots the roots. Keep it barely moist.
• No winter protection. Pot roots freeze long before roots in the ground.

Now your passionflower has a happy home, try another warm-climate climber with the guide to growing bougainvillea in a pot. There are more ideas in the flowers and plants section.

Frequently asked questions

Can you grow a passionflower in a pot in the UK?

Yes, passionflowers grow well in pots across the UK. Blue passionflower (Passiflora caerulea) is the most reliable choice. Use a pot at least 30cm across in full sun, with an obelisk or trellis. The main challenge is winter, as roots in pots freeze more easily.

How big a pot does a passionflower need?

Start with a pot at least 30cm wide and deep. Move up to a 40-45cm pot within a couple of years as the plant grows. A heavy pot also stops a tall, leafy plant blowing over in wind.

What compost should I use for a potted passionflower?

Use loam-based John Innes No.3 mixed with some horticultural grit. The loam holds nutrients and adds weight, and the grit helps drainage. Multipurpose compost alone dries out fast and breaks down quickly. Top-dress with fresh compost each spring.

How do I overwinter a passionflower in a pot?

Move the pot somewhere sheltered, or wrap it if it stays outside. A porch, cold greenhouse or spot against a house wall all help. Outside, wrap the pot in fleece or bubble wrap to protect the roots. Keep the compost barely moist.

Why is my potted passionflower not flowering?

Usually too much shade or too much nitrogen. Passionflowers need full sun to flower well. Switch to a high-potash tomato feed rather than a general one. Young plants often flower better from their second year.

Can you get passion fruit from a potted plant in the UK?

Sometimes, after a warm summer in a sunny, sheltered spot. Blue passionflower fruit turns orange and is edible when fully ripe, but bland and seedy. For tasty passion fruit, grow Passiflora edulis in a heated greenhouse or conservatory.

How often should I water a passionflower in a pot?

Every few days in summer, and daily in a heatwave. Check by pushing a finger into the compost and water when the top few centimetres are dry. In winter, water only enough to stop the compost drying out completely.