Passion Flower Overview
|Official Plant Name||Passiflora|
|Common Name(s)||Passion Flower|
|Hardiness Rating||Varies by type|
|Toxicity||Most toxic, though some have fruits edible when fully ripe|
|Foliage||Evergreen, simple leaves|
|When To Sow||April, May, September, October|
|Flowering Months||May, June, July, August, September|
|When To Prune||March|
Full Sun / Partial Shade
8 – 12M
2.5 – 4M
May – September
Chalk, Loam, Sand
Moist but well drained
You’ve probably heard of passion fruit, but what about passion flower?
Passion flower (Passiflora) is a flowering vine with hundreds of variants, one of which (P. edulis) produces the colourful, seed-filled passion fruits you might find in your fruit bowl.
All varieties of this striking vine display dark green leaves and distinctive, tropical-looking flowers, with flat, open petals, showy stamens and hair-like coronas. Passionflower comes in many colours, including purple, pink and blue, and can add an ornamental, exotic look to your garden.
Being native to South America and southern parts of the USA, passionflower favours a warm climate. When growing the plant in the UK, you should therefore choose a sunny, sheltered area of the garden, or plant it in a container, so that you can bring it inside during winter.
In this in-depth guide, we’ll share all the background knowledge, information and growing tips you need to successfully grow passionflower in a UK climate – and bring those tropical holiday vibes to your rainy old Blighty garden.
Background, Origins & Varieties
Passion flower originates mostly from Central and South America, with the exact locale depending on the variety. Within the Passiflora genus, there are over 500 species, meaning that it can take many forms, including perennials, annuals, shrubs, climbers and trees.
Two of the most well-known varieties are P. edulis, a tropical, perennialvine which produces purple and white flowers, as well as edible purple and yellow passion fruits, and P. caerulea, a deciduous or semi-evergreen climbing shrub, with blue flowers. These varieties can grow to 1.5 metres and 8 metres respectively.
Passiflora flowers are very distinctive. They are approximately 10 cm wide, with a flat petal base, protruding stamen, and colourful corona (delicate, hair-like appendages) between the flower’s corolla and stamen. The flowers are extremely attractive to pollinators (they are great for encouraging butterflies into your garden), but usually, only remain open for a day.
The name ‘passion flower’ is believed to date back to the 1500s, when Catholic missionaries in South America began associating the flower with the Crucifixion of Christ (an event also called ‘The Passion’). Different parts of the flower were said to symbolise the disciples, the crown of thorns, the nails on the cross, leather whips, the spear, and Jesus’s wounds.
Today, passion flower is also known as Passion Vine, Apricot Vine and Maypop, due to the fact that it usually flowers in May. It is used as a flavouring, and certain species, such as P. incarnata, are also known to have a calming or tranquilising effect. This has made it popular for medicinal purposes, including the treatment of anxiety, ADHD and insomnia.
Feeding, Care & Growing Tips
It is important to note that the variety of passion flower you are growing will affect the way you care for it. For example, P. incarnata and P. caerulea are resistant to frost, so can be grown outside (although P. caerulea may still require cover in winter). These are recommended for a UK climate.
Many other species are not hardy to freezing temperatures, and should be kept above 5°C, or, in the case of tropical varieties such as P. edulis, above 10°C. These plants need to be brought inside during winter. Make sure to research your chosen variant prior to purchasing, so you know of its specific requirements.
If you’re growing your passion flower outside, always try to choose a sheltered spot, with either full or partial sunlight, avoiding areas that are entirely shaded. Passion flower can also be grown in a sunny area indoors, or in a greenhouse – although some protection may be needed to avoid leaf burn in summer.
You can either plant it in your garden borders, or grow it in a container. Growing passion flower in a container is advisable, as it means you can move it around, control the amount of sunlight it gets, and bring it inside to protect it from frost. It will also help prevent your passion flower from spreading and becoming invasive.
Depending on the variety, passion flower is generally a hardy plant, and will thrive in pretty much any soil type and pH. It does, however, prefer its soil to be fertile – when planting in a container, do so in a high-quality, peat-free compost. There is no need to add fertiliser, unless the plant is not growing.
As far as watering is concerned, you should keep soil moist throughout the summer growing season. Do not allow it to dry out, but make sure it’s not water-logged either – the soil should have good drainage. You can reduce watering during winter.
In order for your vine to grow and look its best, it’s a good idea to place it next to a fence, trellis or other supportive structure, which it can climb on. You can encourage it to do so by using soft plant ties to attach the branches to the support, at regular intervals, whilst it’s growing.
Habitat & Growing Conditions
The native habitat of passion flower stretches from southern USA, through Central America and down to Brazil in South America. Some varieties are also found in South East Asia and Oceania.
Although it originates from warm climates, many varieties are hardy, and can do well in much milder climates, including the UK. In some warmer areas, the plant can even become invasive.
Passion flower grows in anything from indirect to full sunlight. It favours a moist, fertile soil, with a neutral pH and adequate drainage. It does not like to be water-logged, as this can lead to wilting, fungus and root rot.
Pruning Passion Flower
The first pruning of your passion flower should occur just after planting. Trim back the growing shoots, to encourage the plant to branch at the base, and grow in a more attractive shape. This is also the time to start training your plant to grow along a fence or trellis, by tying its shoots periodically along the fence.
Once your passion flower reaches maturity, you should prune it every spring, to encourage flowering. Take this opportunity to trim back any extended shoots, re-shaping it into your desired form. If growing outside, you should also make sure to remove any limbs damaged by frost.
Where To Buy Passion Flower
You can purchase passionflower seeds and seedling plants from garden centres, nurseries and online retailers. The most popular species available in the UK is the hardy, blue-flowered P. caerulea – if you want another variety, you may need to shop around to find a specialist grower.
Growing passion flower from seeds is not the quickest or easiest option. Seeds sprout best when they are fresh, and it is recommended to soak them overnight prior to planting, to break down the seed shell and assist with germination. Even so, it can take seeds up to a year to sprout.
Many garden centres and supermarkets will only sell passion flower in season, when the plant looks its best. To purchase passion flower out of season, find a nursery that grows it outdoors, meaning the plant should be hardier, and able to withstand being planted in colder weather.
If you know someone with a passion flower, it is also possible to propagate it from cuttings or layered shoots. See below for more information on growing passion flower from cuttings.
Common Diseases & Problems
There are several diseases and problems that are common to passion flower. One disease to watch out for is Cucumber mosaic virus (CMV), which can cause a mottled yellow appearance, stunted growth and a reduction or distortion of fruit. Infected plants may need to be destroyed to prevent the virus spreading.
Passion flower is also susceptible to pests, including aphid, whitefly, red mite spider and mealybug. This is particularly true if you are growing your plant in a greenhouse, as these pests favour a warm environment. Check your passion flower regularly for signs of infestation.
As with many plants, you should also watch out for any signs of a fungal infection. Symptoms can include black patches and visible mould. Help to avoid this by ensuring the plant is in full sunlight, and that you only water the soil at the base of the plant, not the leaves.
Other than these diseases and pests, the most common problems that affects passion flower are wilting, wind scorch and blackened leaves, which may be caused by harsh weather or winter frost.
Frequently Asked Questions
Can you eat passion flower fruit?
You can eat the fruit of some passion flowers, but not all. The P. edulis variety is the one which produces the purple, egg-shaped fruits that are commonly eaten. P. caerulea also produces edible orange fruits, which can be eaten only when fully ripe.
It is important to wait for the passion fruits to drop from the plant, rather than picking them, to know that they are ready to be eaten. Non-ripe passion flower fruit should not be consumed, as it can cause gastronomical upset.
Can you make tea from passion flower leaves?
Yes, you can make tea from passion flower (P. incarnata) leaves. Mix 1tsp of dried passionflower into a cup of boiling water, to make a fragrant herbal tea. If you prefer, you can also buy pre-packaged passionflower tea at many health food shops.
Passionflower tea is widely believed to have a calming effect, and can be used as an alternative medicine to treat conditions such as anxiety and insomnia. You should always consult your doctor before taking passionflower, especially if you are on any other medication. Do not drink passionflower tea if you are pregnant or breast-feeding.
When do passion flowers bloom?
This somewhat depends on the variety and growing conditions, but generally speaking, passion flowers are likely to bloom anytime from mid spring to late summer. The flowering period is followed by fruiting.
You can encourage blooming with annual pruning, and by ensuring your passionflower has sufficient sunlight. If your plant still doesn’t bloom, try adding a high-potassium liquid fertiliser to the soil once a week during the spring and summer months.
It is also worth noting that many passion flower blooms only last a day, so you will need to be present and checking on the plant regularly if you don’t want to miss it!
What is eating my passion flower leaves?
Passion flower leaves make a popular food for a variety of insects, particularly butterflies. Butterflies will also often lay their eggs on passion flower vines, which leads to them being munched by hungry caterpillars.
Other potential culprits include beetles, slugs and snails. Ants will also feed on the base of the leaves, although they do not cause as much destruction as caterpillars. Infestations of aphids and red spider mites, which feed on the plant’s sap, can also cause changes in the appearance of leaves.
To reduce the risk of your passion flower leaves turning into an insect banquet, try surrounding the base of the plant with a strip of copper, to deter slugs and snails, and remove larger visible bugs by hand. In extreme cases, the use of an insecticide may be required.
Can you grow the flower from cuttings?
Yes, you can grow passion flower from cuttings. To do so, use sharp pruners to take stem cuttings of around 15cm from the plant, early in the growing season. Remove the leaves at the bottom of the cutting, and dip the end in a rooting hormone.
Place the cuttings 1 – 2cm into a potting mix, and keep them moist and warm, although initially out of direct sunlight. After about a month, new roots should begin to take hold.
Should you cut back passion flowers?
You should prune passion flowers annually, ideally in early spring, to encourage the next flowering. You can use this opportunity to cut back or reshape passion flowers which are growing out-of-hand or in unwanted directions. You do not need to de-head passionflower during the growing season.
Does the plant need full sun?
Passion flower can grow in full or indirect sunlight, but will not thrive in fully shaded areas. If your plant is not flowering, a lack of sunlight could be the problem. Your plant should receive at least 4 hours of sunlight a day – more if possible.
April is a freelance writer who specialises in writing about home and garden design and the environment. She is an avid wildlife-enthusiast and adventure-seeker, and feels happiest when in the Great Outdoors.