Passion flowers (Passiflora)
The genus Passionflower (Pasion Flower or Passiflora) belongs to the Passionflower family (Passifloraceae). It comprises over 530 species as well as numerous hybrid varieties resulting from breeding. Passion flowers are predominantly native to tropical and subtropical South America as well as Central and Southern North America. Further types thrive in Australia, Asia and Madagascar.
Appearance and growth
Passion flowers are usually persistent, herbaceous or woody plants. They grow mainly as climbing plants, only a few species are shrubs or trees. In their leaf axils, the plants form tendrils, with whose help they can hold on to other plants or latticework and thus climb up. The alternate stalked stem leaves are differently developed. In the case of the Blue Passion Flower, for example, they are structured in several lobes. The growth height of the species and varieties cultivated here as tub plants is between 50 centimetres and 4 metres.
Passiflora produces radially symmetrical flowers which, depending on the species, can have a diameter of less than one to 18 centimetres. The striking flowers are composed of several free petals and a corona of filamentous staminodes, i.e. sterile stamens. In its centre stand the five fertile stamens and three scars, which are also conspicuously shaped and tower above the flower. Christians saw in the blossom a symbol of the Passion of Christ: the stamens were interpreted as the wounds of Christ, the three scars as the crucifixion nails, while the aureole of stamens was understood as the crown of thorns. The generic name Passionsblume also goes back to this interpretation. The species and varieties we cultivate as tub plants bloom from early summer to autumn, sometimes even into winter. The colour spectrum of the flowers ranges from white to red, yellow and violet, and after fertilization edible fruits are formed which are botanically assigned to the berries. They are spherical to oval and have firm skin. The fruits often contain a bitter to sweetish or sour tasting juice with many seeds. The individual seeds are surrounded by a gel-like tissue (pulp). While the fruits of the Blue Passion Flower are about five centimetres in size, passion fruit can grow up to twelve centimetres.
Location and substrate
All Passion Flowers prefer a bright and sunny location without congesting heat and an even water supply – the soil should always be moist. However, waterlogging can lead to root and stem rot. Under optimal conditions (most species require a fertiliser plant) even fruits are formed, but in the ornamental forms they are smaller and less tasty than passion fruit, the well-known and popular fruit of the passion fruit (Passiflora edulis). A lot of sun and warmth are the best conditions for the Passion Flower to form many flowers. Passion Flowers can stand outside as tub plants from early summer to autumn. Commercially available pot plant soil is suitable as a pot substrate, which can be enriched with clay granulate to make it more permeable. With growth heights of over four metres, passion flowers – planted on a climbing aid – are also ideal as a flowering privacy screen for terraces or balconies. Our tip: Place the beautiful climbing plant near a seat. So you can enjoy their pretty flowers during the summer months. The Blue Passion Flower is also cultivated as a pure houseplant and looks good in the conservatory.
When planting Passiflora, it is very important that you choose a sufficiently large and, above all, heavy plant container – this is the only way to ensure the necessary stability. In this way you also have space for a climbing aid directly in the pot. For a good water drainage, it is recommended to place clay fragments over the bottom holes so that they cannot be blocked by soil.
Climbing aids in the our store-Shop
Despite its spectacular appearance, Passiflora is an uncomplicated pot plant. Supply your passion flowers well with water during the growth phase from March/April to September/October. Rainwater or tap water with low lime content is ideal, as most species react somewhat sensitively to a very high lime content. Passion flowers are fertilized exclusively during the vegetation period in one- or two-week intervals with a conventional liquid fertilizer for tub plants, which is added to the watering water. The leaves of the climbing stars should be moistened with water more often in the winter garden to prevent spider mite infestation. Passion flowers should be repotted in a larger container every one to three years as required, when the soil is completely rooted. The best time to do this is at the beginning of the growing season, usually in February or March. The new vessel should be two to three centimetres larger than the previous one.
In early spring, the main cut of Passiflora takes place, in which all side shoots are reduced to three to five eyes. This promotes the formation of new flower buds at the tips of the shoots. To make it easier for passionflowers to spend the winter, the plant can be shortened to scaffold height in late autumn. Passion flowers are not harmed if you cut them back strongly in autumn, but it is better to preserve as much plant mass as possible. In winter, passion flowers naturally dry back. A plant that has already been pruned may have little left after winter. Therefore, it is better to accept the effort of unwinding.
Wintering or winter protection
Passion flowers are sensitive to frost and must therefore spend the winter indoors. The bright winter quarters should have a temperature of between 5 and 15 degrees Celsius, depending on the species and variety. Even in winter, the root ball of Passiflora must never dry out, so the plant must be watered regularly. Don’t be surprised if the plant dries back quite far anyway. This is perfectly normal for passion flowers, as already mentioned.
Tip: To save yourself the hassle of unwinding before winter, you can keep your climbing aid mobile so that you can put it into the house together with the passion flower. Scaffolds that are mounted directly on or in the pot are ideal.
Important species and varieties
One of the best known species cultivated in our country as a pot plant or indoor plant is the Blue Passion Flower (Passiflora caerulea), which originates from northern Argentina and southern Brazil. Other well-known species are the purple granadilla (Passiflora edulis) and the yellow granadilla (Passiflora edulis f. flavicarpa), the juice and fruits of which are available on the market. 50 to 60 species of Passiflora form edible fruits, but only a few of them are actually cultivated for their fruits. In tropical countries, Passiflora edulis, the well-known passion fruit, is cultivated as a useful plant. The popular passion fruit juice is obtained from the fruits of various passion flowers. Very large fruits are produced by the following species, which you can keep very well in conservatories: Passiflora edulis, Passiflora quadrangularis, Passiflora alata, Passiflora ligularis. The robust Blue Passion Flower and the Red Passion Flower (Passiflora vitifolia) are also worth harvesting, while many ornamental varieties produce no or very small, low-sap fruits that are not a pleasure to eat.
Passion Flowers in the our store-Shop
Passion flowers can be propagated in early summer by head cuttings. It is also possible to sow seeds that have been harvested yourself. The seeds are taken from the ripe fruit and the pulp that surrounds the seeds is removed. The seed is sown in a nutrient-poor substrate, the seed is only thinly covered with soil. A germination temperature of 25 to 28 degrees Celsius is indispensable. Passion flowers are easy to cross, resulting in new varieties. Who would like to try himself once in breeding, proceeds as follows: Choose two different Passion Flowers. One flower is separated from the other by a pair of scissors, a small stalk at the end of which the yellow pollen is seated. This is not gripped with the fingers, but with tweezers. Carefully dab the yellow pollen onto the three mostly white scars of the second flower. After this pollination, the flower is wrapped in a bag so that no foreign pollen can interfere. If you have been successful, the flower will ripen into fruit whose seeds carry the genes of a new passion flower variety and will be sown next summer.
Diseases and pests
If the location is too hot in summer, the stressed passion flowers can be attacked by spider mites. These can be controlled with pesticides based on acaricides.
Whether fruit, vegetable and ornamental plants in the garden or indoor plants in the house: spider mites can infest and damage many different plants. Here René Wadas, a herbalist, will tell you his tips on how you can effectively fight the arachnids.Credits: Production: Folkert Siemens; Camera: Fabian Primsch; Editing: Dennis Fuhro, Photos: Flora Press/FLPA, GWI
I am Don Burke, one of the authors at My Garden Guide. I am a horticulturist that cultivates, grows, and cares for plants, ranging from shrubs and fruits to flowers. I do it in my own garden and in my nursery. I show you how to take care of your garden and how to perform garden landscaping in an easy way, step by step.I am originally from Sydney and I wrote in local magazines. Later on, I have decided, more than two decades ago, to create my own blog. My area of specialization is related to orchid care, succulent care, and the study of the substrate and the soil. Therefore, you will see many articles dedicated to these disciplines. I also provide advice about how to improve the landscape design of your garden.