Blue passion flower

Blue passion flower: how do you recognise it?

Habit

Vigorous climber that clings with curly tendrils and climbs to 4–6 m.

Leaf

Alternate, 8–12 cm, deeply palmately 5- (to 7-)lobed, untoothed and dark green; evergreen in mild winters.

Stems

Green, angular stems with curly tendrils in the leaf axils.

Flower

Flat flowers (6–10 cm): 10 white to greenish tepals, a ring of filaments in blue, white and purple, 5 stamens and 3 stigmas; June–September.

Fruit

Egg-shaped, orange fruits (4–6 cm) with red pulp full of seeds, in autumn; edible but bland.

Difference from passion fruit

Passion fruit (Passiflora edulis) has three-lobed leaves and purple fruits with fragrant, sweet-sour pulp; it is not hardy.

Flowering: June–September · Pruning: March–April

Looks like it, but isn’t

• Passion fruit (Passiflora edulis): three-lobed leaves and purple fruits with fragrant, sweet-sour pulp; not hardy.

Why grow it?

• Large, exotic flowers from June to September, with new ones opening all the time.
• Bumblebees and bees visit the flowers.
• Grows fast and covers a wall, fence or pergola within a few years.
• Stays green in mild winters, and also looks good in a large pot on a patio.

Blue passion flower: where does it grow best?

• Full sun, ideally against a south- or west-facing wall: the warmer the spot, the more flowers and the better it gets through winter.
• Sheltered from cold east and north winds; it does best in towns and near the coast, where frosts are milder.
• Any free-draining garden soil will do; it dislikes wet soil in winter.
• It needs support: tensioned wires, mesh or a trellis for the tendrils to curl around. Allow about 2 m width.

Light

Full sun

Legal basis

Any garden soil

Moisture

Normal

Size

5 m tall, 2 m wide

Hardiness

Throughout Belgium, no protection needed

Goes well with

• Star jasmine: An evergreen, fragrant climber for the same warm, sheltered wall.
• Fig: Also loves a warm south-facing wall; together they give a southern feel.
• English lavender: A low, fragrant edging at the foot of the wall, in the same sunny spot.
• Rosemary: Mediterranean, evergreen and aromatic, for the warmest corner by the wall.

Good and bad companions

Goes well with

• Can climb into old, large trees: english oak, scots pine, sycamore, large-leaved lime

Blue passion flower: when and how to plant it?

1. Plant in May, after the last night frost: this gives the plant a whole summer to root before its first winter.
2. Set it 20–30 cm from the wall, where the soil is less dry, and lead the stems at an angle towards the wires.
3. Mix a little compost into the planting soil, but don’t make it too rich: otherwise you get lots of leaves and few flowers.
4. In a pot: choose one at least 40 cm across, with a drainage hole and free-draining compost.

Care

Watering

Water young plants and plants in pots regularly in summer; an established plant in the ground usually copes on its own.

Feeding

A little compost or flowering-plant fertiliser in spring is enough; too much nitrogen gives lots of leaves and few flowers.

Tying in

Guide new stems to the wires in good time, or they will get tangled.

Suckers

It can send up suckers some distance away; dig them out where you don’t want them.

Tip: Choose a spot against a wall of the house: it gives off warmth at night, which helps the plant through winter. Cover the base with a thick layer of mulch in autumn.

Blue passion flower: when to prune it?

Pruning months: March–April.

When: In March–April, once the frosts are over.

How:

• Remove frost-damaged and dead stems and thin the plant out to let in light and air.
• Shorten side shoots to 2–3 buds: it flowers on this year’s new shoots.
• If all the top growth has been killed by frost, cut everything back to just above the ground and wait: it often reshoots from the roots in May–June.

Caution: Not fully hardy: cover the base with a thick layer of mulch in winter. A frosted plant often reshoots from the roots.

Pruning: when and how · Pruning calendar and basic rules

Propagation

Cuttings

In summer, take 10–15 cm cuttings from semi-ripe shoots and root them somewhere warm in a moist, sandy mix under plastic.

Sowing

Sow seeds from ripe fruits indoors in spring, somewhere warm; germination can take weeks to months.

Suckers

In spring, dig up a rooted sucker and replant it where you want it.

Blue passion flower: how does it get through the winter?

Hardy throughout Belgium: no protection needed.

• Not fully hardy. In light frost it stays green; in severe frost (−10 °C and below) the stems and leaves can be killed outright.
• In autumn, cover the base with a thick layer of mulch (straw, leaves or wood chips) to protect the roots: a frosted plant will then usually reshoot.
• Keep a plant in a pot frost-free and in the light over winter, for instance in a cold greenhouse; water sparingly.

Diseases and pests

• Frost damage: Brown, withered stems after a severe winter. Wait until April–May and then cut out the dead wood; new shoots often appear from the base.
• Few flowers: Too much shade or too much fertiliser. Give it a warm, sunny spot and little nitrogen.
• Aphids and red spider mite: Mainly on plants in pots or against a hot, dry wall: aphids on the tips or fine yellow speckling on the leaves. Hose the plant down and don’t let the soil dry out.
• Suckers: Shoots coming up some distance from the plant. Dig them out with a piece of root.

Through the year

• March: Prune as soon as hard frosts are over: remove frosted and dead stems.
• April: Last month for pruning: shorten side shoots to 2–3 buds; pull the mulch away from the base.
• May: Plant after the last night frost; move pots outside; tie in new shoots.
• June: Flowering begins; tie in and water in dry spells.
• July: Full flower; take cuttings.
• August: Flowering; water plants in pots.
• September: Last flowers; the fruits turn orange.
• November: Cover the base with a thick layer of mulch; move pots to a frost-free place.

What can you use it for?

Garden and landscape

Exotic flowering climber for a warm, sheltered south-facing wall or a large pot.

For wildlife

Bumblebees and bees visit the large flowers.

Food and drink

The orange fruits are edible but bland; mainly decorative.

Did you know?

• Spanish missionaries saw in it the Passion of Christ: the filaments are the crown of thorns, the 3 stigmas the nails, the 5 stamens the wounds and the 10 tepals the apostles, without Judas and Peter.
• Each flower is open for just one day; because new buds keep opening, the plant still flowers all summer.
• It is one of the few passion flowers that can stay outdoors in our climate.