Blue passion flower

Climber

Passiflora caerulea

Blue passion flower

A vigorous hardy climber with intricate white, blue and purple flowers and orange fruits, the toughest passion flower.

  • Full sun, Partial shade
  • 8–12 m (26–39 ft)
  • 2.5–4 m (8–13 ft)
  • H4 · Zone 8
  • June–October
  • Evergreen
  • RHS Award of Garden Merit

Overview

Blue passion flower is an evergreen climber with five-lobed leaves and intricate white flowers crowned with blue, white and purple filaments from summer to autumn, followed by egg-shaped orange fruits.

It is hardy to about −10°C (14°F), USDA zones 6–10, and in cold winters may be cut back but regrows from the base. It thrives in Mediterranean and warm-temperate gardens and is a caterpillar food plant for passion-vine butterflies in the Americas.

Grow on a sunny, sheltered wall in any well-drained soil and prune hard each spring to keep it in check.

At a Glance

Sun Full sun, Partial shade
Height 8–12 m (26–39 ft)
Spread 2.5–4 m (8–13 ft)
Hardiness H4 · Zone 8
Flowers June–October
Soil Chalk, Clay, Loam, Sand
Moisture Moist well drained
Habit Spreading, Upright
Water Moderate
Maintenance Easy

Growing Conditions

Min. Temperature -10°C (14°F)
pH Range 6–7.5
Fertility Average
Drainage Free Draining

Aspect Suitability

  • South-facing
  • West-facing

Soil Tolerance

  • Clay
  • Chalk
  • Sandy
  • Loam
  • Acid
  • Neutral pH
  • Alkaline

Foliage

Persistence Evergreen
Colour Green
Leaf shape / texture palmately_lobed

Foliage interest: 12 months of the year

Seasonal Timeline

Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec
Flowering
Foliage
Fruiting
Propagate
  • Flowering Jun Jul Aug Sep Oct
  • Foliage 12 months of the year
  • Fruiting Aug Sep Oct Nov
  • Propagate Apr May Jun Jul Aug

How to propagate

One way to grow more Blue passion flower:

Semi-ripe cuttings Jun Easy

You'll need: Sharp knife, gritty compost

  1. Take 10 cm (4 in) cuttings below a node
  2. Remove lower leaves and tendrils
  3. Insert in gritty compost under cover
How long
15 minutes
It's worked when
high
Then
Pot on and plant out the following spring.

Semi-ripe cuttings root easily in summer. Sow seed in spring after soaking.

Maintenance Calendar

  • Mar Cut side shoots back to two or three buds and remove weak growth
  • May Tie in new shoots to supports
  • Jul Take semi-ripe cuttings
  • Jul Water young plants in dry spells

Garden Design

Works well in: Cottage, Tropical / Exotic, Wildlife-friendly

Exotic-looking flowers on a reliably hardy climber; give it a sunny wall or fence with wires. Can become rampant, so prune each spring.

Companion planting: Clematis, Trachelospermum, Roses, Salvias

Wildlife Value

  • Bees
  • Butterflies
  • Birds
  • Food source
  • Food

Food for birds: August–November

Safety

  • Toxic to humans
  • Toxic to dogs
  • Toxic to cats
  • Toxic to horses

Leaves and stems contain cyanogenic glycosides and are harmful if eaten. Ripe fruit is edible but bland; unripe fruit should not be eaten. An environmental weed in New South Wales and other Australian states and in parts of New Zealand; birds spread the seed.