Passiflora: Greenhouse Plants
FF – frost free only/C – cool, minimum of 7°C (45°F) / W – warm, minimum of 13°C (55°F) / T – tropical, minimum of 18°C (65°F)
The central column of the flower represents the scourging post, the three stigmas the three nails, the five stamens the five wounds, the corona filaments the crown of thorns, the calyx the halo of glory and the ten petals the apostles minus Judas and Peter. This is how the early missionaries in South America compared the various parts of theto Christ’s Passion and how this exotic group of acquired their strange name.
The most commonly grown is Passiflora caerulea which is hardy in some parts of Britain, producing its white flowers with mauve-blue filaments between June and September. However, this is also an excellent specimen for the frost free house. Fruits are often borne which are ornamental rather than edible. A more unusual choice for the frost free or cool house is P. herbertiana from Australia with three-lobed leaves and small orange-green flowers in late summer. If you want to grow passion fruits to eat, then P. edulis, the Purple Granadilla, whose wrinkly brown fruits are often seen for sale in supermarkets, is a good one to try. This likes warm conditions and should produce fruit in its second year from seed. Incidentally they do not have to become wrinkled before they are fit to eat; a purplish-yellow colour and slight toughening of the skin is a sure sign that they are ripe. It will need a fair bit of head room to fruit well. Flowers are white and purple; interesting but not the showiest. Fruit of P. ligularis, the Sweet Granadilla, which also likes warm conditions is in my opinion the best flavour; this is an even larger plant from Peru with big heart-shaped leaves. The fruit is quite large and is ripe when yellow. P. quadrangularis the Giant Granadilla has an extremely showy flower and edible fruits but prefers a more tropical temperature. P. mollissima for the warm house has beautiful pale pink flowers and long edible fruits which give it the name of Banana Fruited Passion Flower. P. amethystina, a glorious blue-purple, P. antioquiensis, shocking pink, P. caeruleo-racemosa a hybrid with very freely produced purple flowers and another hybrid P. X allardii of subtle pinks and purples are all recommended for the warm house. P. coccinea is spectacular for the tropical house with its bright red flowers. P. racemosa is also tropical but is smaller growing and bears fewer, though interesting, dark reddish-purple flowers.
Plants are easily raised from seed or byin May or June. After flowering plants can be pruned hard, cutting back the flowered shoots to within a bud or two of older wood. It is inadvisable to cut into very old wood without leaving a younger spur as they may fail to grow back. Be ever vigilant against red spider mite which love to attack them and, to a lesser extent, mealy bug.