Passion flower likes moderately fertile, well-drained but reliably moist soils. It will thrive in any soil type and is not fussy about acidity or alkalinity.
Full sun or dappled shade is best, with shelter from cold, drying winds. A south, south-west or west-facing wall is ideal.
If growing passion flower in a south-facing glasshouse or conservatory, shade from direct sunlight may be needed to prevent the leaves from scorching.
Passion flower tends to flower particularly well when roots are restricted, such as in a container or pathside border. When planting in a container, use either John Innes No 3 potting compost, or good quality peat-free compost.
Watering and feeding
Water passion flowers freely during the growing season (especially container-grown specimens) to ensure that they don’t dry out. Water them more sparingly during the winter, allowing the compost surface of container grown specimens to begin to dry out between waterings.
Regular feeding is not necessary and can lead to excessive growth at the expense of flowers. However, if plant growth is weak to
p dress garden specimens with a general fertiliser
such as Growmore, Vitax Q4 or blood fish and bone, using the application dose on the packet (or 50-70g per sq m (1½-2oz per sq yd) if no dose is given).
The hardiness of passion flower varies between species and cultivars:
- Passiflora incarnata is fully hardy, but should still be grown in a sheltered spot
- P. caerulea is frost hardy, so is suitable for outdoor growing in milder regions of the UK only, and may require some winter protection. Note that in some gardens it can become invasive
- P. mollissima, P. × exoniensis, P. antioquiensis, P. × alatocaerulea, P. × allardii, P. × caeruleoracemosa, P. manicata and P. alata require a minimum temperature of 5-7°C (41-45°F) so are best suited to glasshouse or conservatory conditions
Other species, including P. edulis (the passion fruit or granadilla), P. coccinea, P. racemosa, P. vitifolia and P. quadrangularis require tropical conditions and minimum temperatures of 10-16°C (50-61°F), depending upon the species. Their cultivation is not dealt with here.