Photo: P. Lameiro / Public domain / Wikimedia Commons

Passion flower

Passiflora caerulea

An intricate tendril climber with blue-and-white flowers that bees and butterflies love. It wants afternoon shade and steady water in Dubai, and its leaves and stems are poisonous.

Mature size3–12 m tall, 1–2 m spreadGrowthFastSunSun/part shadeWaterModerate

Heat: 3 of 5

Salt: 2 of 5

Drought: 2 of 5

Shade: 3 of 5

Ease of care: 3 of 5

Use in a design Get it looked after

Season

Through the Dubai year

How Passion flower behaves through Dubai's seasons, month by month.

JJan

FFeb

MMar

AApr

MMay

JJun

JJul

AAug

SSep

OOct

NNov

DDec

Avg high °C

24°

26°

29°

34°

38°

40°

42°

40°

36°

31°

27°

Best planting window

Spring growth flush

Flowering flushes

Apr – Jun

Sep – Nov

Shade, mulch and deep watering

Prune after flowering

Best planting window: Mar–Apr, Oct–Nov
Moderate temperatures help roots establish before summer.
Spring growth flush: Mar–Apr
Flowering flushes: Apr–Jun, Sep–Nov
NC State records early summer to early autumn in North Carolina; in Dubai expect spring and autumn flushes.
Shade, mulch and deep watering: Jul–Aug
Flowering and growth ease in peak heat; the plant needs afternoon shade and steady water.
Prune after flowering: Jan–Feb
NC State advises cutting the year's growth back by half and deadheading; avoid removing too much at once.

In its native range the blue passionflower blooms from early summer to early autumn, according to NC State, and in a warm climate it stays evergreen. In Dubai, expect its best flushes in spring and autumn, with growth and flowering easing in the heat of July and August, when afternoon shade, mulch and deep watering matter most. Fruit ripens from green to yellow and deep orange from late summer. Prune after the main flowering, cutting the year's growth by half. Plant in March and April or October and November.

Meet the plant

Meet the Passion flower

Meet the passion flower, a bloom so elaborate that it looks assembled rather than grown. A saucer of pale petals carries a crown of banded blue and white filaments, with purple styles and yellow-green stamens at the centre, and the whole structure is held out on a long stalk as if for inspection. The name Passiflora comes from Latin American priests who used the flower's parts to symbolise the Passion of Christ.

The technicality is the tendril. A coiling green thread at the base of every leaf finds a wire or a trellis bar and wraps itself around it, so the plant climbs fast and holds firm, and, according to NC State, does so without damaging surfaces. Bees and butterflies visit the flowers, and the plant is a larval host for butterflies.

The mood is intricate and slightly otherworldly. In a Dubai garden it suits a shaded pergola or a trellis against a wall that gets afternoon shade, where it gives a cool, detailed, tropical feel that is a world away from bolder bougainvillea.

Passion flowers are among the most elaborate blooms a garden can grow, and the species most often seen, Passiflora caerulea, shows why. NC State Extension describes saucer-shaped flowers 2.5 to 3 inches (about 6 to 8 cm) wide on long stalks: white to whitish-pink tepals, a crown of filaments banded blue, white and dark purple, three purple styles and five greenish-yellow stamens, followed by orange fruit. It is a fast, tendril-climbing vine native to South America, evergreen in warm winter climates, and its coiling tendrils grip trellis, arbour and fence without harming the surface.

The technical points matter in Dubai. NC State records that it grows in partial shade to full sun in moist, well-drained soil, adapts to clay, loam or sand and any pH, and likes high humidity. Dubai's dry air is the opposite of that, so give it afternoon shade, mulch and steady water, and avoid a bare, reflective west wall. NC State advises pruning after flowering to reduce its size, cutting the year's growth by half, and warns that taking off too much top growth at once can lead to root problems. Good air circulation helps against fungal disease.

If you want fruit, the species to grow is the passion fruit, Passiflora edulis: Wikipedia describes a purple-fruited form that is smaller, less acidic and richer in aroma, and a larger yellow form, and notes that it needs protection from frost and suffers from woodiness virus and fusarium wilt. Blue passionflower fruit is edible but bland. Treat the plant with respect: NC State lists the leaves and stems as a medium-severity poison, with cyanogenic glycosides, and Wikipedia notes that it can send up underground shoots from the parent.

Design

Where to use it

Trellis or pergola climberWall climber with afternoon shadeContainer climberPassion fruit crop

Put it on a trellis, pergola or wire frame where it gets morning sun and afternoon shade, ideally with a mulched, well-watered root zone, because Dubai's reflective walls and dry air are hard on it. Contain the roots in a large pot or an edged bed, since Wikipedia notes underground shoots can appear metres from the parent. Keep it where children and pets will not chew leaves or stems, and prune it after flowering, taking no more than half the year's growth.

Hibiscus

Hibiscus' large blooms and its enjoyment of warmth and regular water complement the passion flower's intricate flowers in a shaded tropical corner.

Lantana

Lantana adds butterfly-friendly colour at the base, and its heat tolerance covers the beds near the vine's roots.

Arabian Jasmine

Arabian jasmine's evening scent layers beneath the passion flower's visual intricacy on the same trellis or pergola.

Bougainvillea

Bougainvillea on a neighbouring, sunnier wall gives lower-water colour while the passion flower takes the shadier, more sheltered position.

Care guide

How to grow it in Dubai

Watering: Summer: Water deeply two or three times a week and mulch; NC State records that it likes moist, well-drained soil and high humidity.
Winter: Reduce to about weekly as growth slows.
Establishment: Water regularly through the first season while the roots establish.
Soil: Moist, well-drained soil; NC State records clay, loam and sand, and any pH.
Feeding: A light, balanced feed through the growing season.
Pruning: Prune after flowering, cutting the year's growth back by half and deadheading regularly, as NC State advises. Do not remove too much top growth at once, because NC State warns that roots may develop fungal disease.
Planting: Plant March, April, October or November on a trellis or wires in morning sun and afternoon shade. Contain the roots in a large pot or edged bed.
Pests: Fungal disease where air circulation is poor (NC State)Passion fruit woodiness virus, spread by aphids and mites (Wikipedia)

Avoid these

Common mistakes

Planting it on a bare, reflective west wall. It likes humidity and moist soil, so give it afternoon shade, mulch and steady water.
Pruning it hard all at once. NC State warns that taking too much top growth at once can lead to root fungal problems.
Letting the roots run. Wikipedia notes that underground shoots can appear metres from the parent, so contain it.
Assuming every passion flower gives good fruit. Blue passionflower fruit is edible but bland; grow Passiflora edulis for the harvest.
Planting it where children or pets can chew the leaves and stems, which NC State lists as a medium-severity poison.

Extra notes

Good to know

NC State records blue passionflower as native from Bolivia to Brazil and northern Argentina, and as the national flower of Paraguay.
The name Passiflora refers to the Passion of Christ; Latin American priests of the 15th and 16th centuries used parts of the flower as symbols (NC State).
Wikipedia notes that blue passionflower is used as a rootstock for grafting edible passion fruit species.
The purple form of passion fruit is smaller, less acidic and more aromatic than the larger yellow form, which holds cyanogenic compounds in the peel and juice (Wikipedia).

Toxicity: NC State lists blue passionflower leaves and stems as a medium-severity poison (cyanogenic glycosides), with severe nausea, vomiting, drowsiness and irregular heartbeat recorded; the fruit is edible but bland. Keep children and pets from chewing leaves and stems.

Pros

Spectacular blue-and-white flowers that attract bees and butterflies
Fast, tendril-climbing cover for trellises, arbours and fences, without harming surfaces
Evergreen in warm winter climates, per NC State Extension
Passion fruit (P. edulis) adds an edible, richly flavoured crop
Larval host plant for butterflies

Cons

Leaves and stems are poisonous (cyanogenic glycosides), according to NC State
Likes humidity and moist soil, so Dubai's dry air and summer sun are hard on it
Can send up underground shoots from the parent plant, so the roots need containing
Prone to fungal disease in poor air circulation or after heavy pruning

FAQ

Common questions

Which passion flower should I grow in Dubai?

For flowers, Passiflora caerulea, the blue passionflower, which NC State rates as fast-growing, evergreen in warm winters and tolerant of sun or partial shade. For fruit, Passiflora edulis, the passion fruit. Both want afternoon shade, mulch and steady water in Dubai's dry heat.

Is passion flower poisonous?

NC State lists the leaves and stems of blue passionflower as a medium-severity poison (cyanogenic glycosides), with severe nausea, vomiting, drowsiness and irregular heartbeat recorded. Keep children and pets from chewing them. The ripe fruit is edible but bland.

Can I eat the fruit?

Blue passionflower fruit is edible when ripe but bland; Wikipedia notes a mild blackberry flavour in warm climates. For real flavour, grow passion fruit (Passiflora edulis), whose purple form is smaller, less acidic and more aromatic than the yellow form.

How hard can I prune it?

Prune after flowering, cutting the year's growth by half, as NC State advises, and deadhead regularly. Do not remove too much at once, because NC State warns that the roots may develop fungal disease after heavy pruning.

Will it spread?

It can. Wikipedia notes that blue passionflower sends underground shoots up to about 15 feet (4.5 m) from the parent plant and that it can become invasive in places, so grow it in a large pot or an edged bed.

Not sure how it suits your garden?

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