How to grow passion flowers

Choosing a passion flower

Passion flowers generally fall into two groups. The first are the hardy types that are able to grow outside in a sunny, sheltered location in the garden. The second group are tender and you will to grow them in a conservatory or warm greenhouse. So, the first decision you'll need to make is whether to grow border passion flowers or conservatory passion flowers, if you have a suitable indoor space. You can try them as houseplants too, but they need a light position and lots of space to grow, as these climbers are usually at least 3m (10ft) tall

Find out more about border and conservatory passion flowers:

Border passion flowers

Border passion flowers

Conservatory passion flowers

Conservatory passion flowers

You can choose which flower colour and shape you’d like.

• Hardy passion flowers are still only truly hardy in towns, cities and mild areas, such as around the coast in the UK. The blue Passiflora caerulea is widely available at garden centres, as is its all-white form:  Passiflora caerulea ‘Constance Eliott’ 
• Tender passion flowers have blooms that range in colour from reds and yellows to purples and blues. The flower shapes range from simple starry bells, such as Passiflora citrina, to exotic jelly-fish-like forms of Passiflora quadrangularis. All will need room in a conservatory or heated greenhouse to grow and flower well.

Finally, if you want to try growing edible passion fruit, it’s something that’s fun to try as it usually results in a few fruits (but not big crops). The two to try in a conservatory or greenhouse are Passiflora edulis (the passion fruit or Purple granadilla) and P. quadrangularis, (Giant granadilla) although the most reliable for fruiting is P edulis.

Find out more about edible passion flowers:

Edible passion flowers

Edible passion flowers

Buying

Plants for sale are usually of flowering size and available in 1 or 2 litre pots. They are available at both garden centres and via mail order.

Tender passion flowers that need to be grown in a heated greenhouse or conservatory and are usually only available from nurseries specialising in climbers or tropical plants. For those looking for more specialist information, the Passiflora Society International provides a lot of useful information on these plants

Use the RHS Find a Plant tool for specialist nurseries near you or with plants for mail order purchase.

Planting Outdoors

• Plant hardy passion flowers in the spring after the cold weather has passed (typically late May/early June)
• Hardy passion flowers planted in the garden border, produce the best growth and flowers when in a sunny, sheltered position away from cold drying winds. A south- or west- facing fence or wall is ideal
• Hardy Passiflora caerulea can reach 10m (33ft) high and so needs space to grow and flower well
• Passion flowers climb by means of tendrils and need to be planted and trained against a trellis or horizontally-wired fence or wall on which the tendrils can cling

Planting Indoors

• Tender passion flowers can be grown in containers, starting with a 30cm (12in) wide pot, in the greenhouse 
• Provide light shade for tender passion flowers grown in a conservatory or greenhouse to prevent the foliage becoming scorched in hot weather

Watering

Water passion flowers in the garden once a week during dry spells and container plants as soon as the surface of the soil looks dry. Flower buds may drop if the soil becomes too dry and the plant wilts. Water container plants less frequently during the winter to avoid root rot from the soil remaining too wet

Feeding

If growth and flowering is weak, feed plants in the ground in spring with a general fertiliser such as Growmore. Plants in containers should be fed using a liquid feed, such as Phostrogen, every four to six weeks during the growing season (March to October). During the winter, no feeding is required as the plant will be dormant

Deadheading

No deadheading is required, as passion flowers flowers drop naturally.

Repot passion flowers growing in containers every 2-3 years.

Overwintering hardy passion flowers

While Passflora caerulea is hardy in milder regions of the UK, in colder areas protect the stems by wrapping with insulating fleece

Overwintering tender passion flowers

Passiflora mollissima, P. × exoniensis, P. antiqueness, P. × alatocaerulea, P. × allardii, P. caeruleoracemosa, P. alata, P manicata all require a minimum temperature of 5-7°C (41-45°F) so are best suited to heated but cool conditions in a glasshouse or conservatory.

Overwintering edible passion flowers

P. edulis (the edible passion fruit or purple granadilla) and P. quadrangularis (Giant granadilla) require tropical conditions and winter temperatures no lower than 10-16°C (50-61°F)

Prune your passion flower once a year in early spring if necessary. Flowers are produced on the new growth, so pruning entails removing the old flowered stems, while retaining a framework of strong, healthy stems. Pruning helps to keep the plant tidy and within bounds.

Renovate overgrown plants, by cutting back the stems to 30-60cm (1-2ft) from the base. Renovation should only be done every few years as it will weaken the plant if performed too often. Reduce excessive numbers of new shoots that may appear, retaining only the strongest. Be aware that flowering is often delayed for a year or two after renovation.

You can make new plants from your passion flowers from cuttings, layering or seed.

Layering

Layering is the easiest method of propagating passion flowers and flowering sized plants can be obtained almost immediately. The method enables rooting of the layered stem while it is still connected to the mother plant. This means it is almost always successful.

Softwood cuttings

Softwood cuttings are also possible and are made by taking cuttings of the soft and flexible young shoot tips in spring and summer. These root readily when planted in a multi-purpose compost and kept in a heated propagator or enclosed plastic bag to retain humidity.

Semi-ripe cuttings

Semi-ripe cuttings are an easy way to propagate Passiflora. These are taken using stems that are soft at the tip but which have hardened at the base. They will root quickly when taken in summer.

Seed

​Passion flower may be propagated from seed, but the seedlings may not grow to be the same as the parent plant. Soak the seeds in tepid water for 24 hours to soften the hard seed coat. Then sow into multipurpose compost and keep covered at a temperature of 25°C (77°F) until seedlings appear.

Flower buds may drop if the soil becomes too dry and the plant wilts (see Watering above)

In the garden

Pests such as aphids can be a nuisance on young growth
Plant viruses such as cucumber mosaic virus can be troublesome

Under glass

Passion flower is vulnerable to a range of pests indoors including Glasshouse red spider mite, Glasshouse whitefly, scale insects and mealybug

If you’re a member of the RHS, you can use our online Gardening Advice service, via MyRHS for any gardening questions.