Passiflora species for cultivation
Passiflora caerulea is native to Argentine, Brazil and Paraguay. It is a climbing perennial plant where the stems eventually lignify. The leaves are entire, often 6-7 lobed with 2-4 nectaries on the petiole. They can reach a size of 16-18 cm but are mostly somewhat smaller. The bracts are pale green and the flowers are white, blue, and dark violet and usually 7-9 cm in diameter. The outside of the sepals is green but the inside is white as the petals. There are four whorls of filaments in the corona banded with the colors mentioned. The outer whorl has up to 2.5 cm long filaments while the inner ones are only two mm long. The orange fruit is edible. P. caerulea is probably the easiest to grow. It is applicable for both the windowsill, the winter garden as well as outdoors since it tolerates temperature down to -15℃ and if several years old even lower temperatures. Plant it outdoors in May in a site, which is relatively dry during winter. Otherwise, there is a greater risk that it will die due to rot rather than to cold. When planted outdoors P. coerulea produces root shoots, which may be used for propagation. The root shoot should be removed to promote flowering of the main shoot.
Passiflora cincinnata is widely distributed in South America and well suited for growing in greenhouse or winter garden where it will flower most of the summer and autumn. It has fragrant flowers 7-12 cm in diameter.
P. cincinnata is a perennial climbing plant with deeply 5-lobed leaves with two nectaries near the base of the petiole besides small nectaries on the leaf edge at the base of the lobes. The flowers are placed solitary in the leaf corners. The tepals are light-violet and curved backwards. At the base the three green bracts are provided with two (or four) large green nectaries. The sepals are green on the outside but violet on the inside. They are slightly keeled and with a hook-shaped green beak at the tip. The corona has several whorls. The outermost has about 4 cm long filaments, which are strongly wavy, deep red-violet at the base, lighter in the middle and outermost blue-violet. The inner whorls have about two mm long violet filaments. The color intensity varies with area of origin. In the bud, the corona is crumpled but it expands shortly after the flower opens so the filaments almost hide the corolla. The fruit is egg-shaped, 5-6 cm long and greenish with white dots. When growing in a greenhouse or winter garden the winter temperature must not be below 12℃. It can be propagated by cuttings.
Passiflora x decaisneana
Four active nectaries and two stipules
Passiflora x decaisneana
In several European botanical gardens Passiflora. x decaisneana is confused with P. quadrangularis, which is supposed to originate from the northwestern South America although its distribution is not well known. P. x decaisneana is a hybrid between P. alata and P. quadrangularis. The hybrid is clearly destinguished from P. quadrangularis by the red inside of the tepals, and the stipules are max. 1.9 cm long, while the tepal inside in P. quadrangularis is almost white and the stipules are 2.5-4 cm long. The mistake was clarified in 1996.
The stems are square and winged. The leaves are entire and up to 25 cm long usually with four nectaries placed in pairs on the petiole (lower photo). The colorful fragrant flowers are solitary in the leaf axils and may reach a diameter of 12.5 cm. The petals are green on the outside but the inside has the same red color as the petals. There are 5-6 whorls in the corona where the filaments in the two outermost whorls are 5-7 cm long with a banded coloration in lilac and white. The filaments in the inner whorls are max. 4 mm. P. x decaisneana hybrids with other species, and with P. coerulea up to 17 cm long edible fruits are produced.
It is a rapidly growing climbing plant, which demands a pot of at least 30 cm in diameter. If planted freely in a greenhouse, it may cover several square meter in a growing season with 4-6 m long shoots. Flowering begins late in summer and continues in periods of a couple of weeks in the autumn. It can be propagated by cuttings.
The lower photo shows four active nectaries on the petiole. At the base of the petiole two stipules are present and a tendril (brown) as well as a small wilted flower bud.
Passiflora racemosa grown in a greenhouse
Passiflora racemosa grows in the southeastern Brazil near the Atlantic coast, where the soil is sandy, the days are warm and often windy and precipitation is sparse. The three-lobed entire leaves are leathery (xeromorphic character) with 0-4 small nectaries on the petiole. Leaves with only two lobes or without lobes occur.
The flowers are 8-10 cm in diameter with three whorls in the corona. The outer whorl has up to 12 mm long white filaments with a red-violet band. The inner whorls have 2-3 mm long greenish filaments. The anthers have white pollen (the others shown species have yellow pollen). The fruit is green, cylinder-shaped and up to 7 cm long.
As a main rule flowering occurs from older lignified stems. The inflorescence is normally a leafless hanging raceme with 1-3 flowers per node. There is no bract but its stipules are often present. Since both bracteoles and the keeled sepals are just as red as the petals during bud development, the up to 75 cm long inflorescence with up to 30 buds is very eye catching, although often only one or max three flowers are open simultaneously. The flowers can also appear solitary on shoots with reduced bracts. Such shoots will normally continue growth and develop into normal leaf bearing stems. The flowers are pollinated by humming birds and have no scent.
Propagation by cuttings is difficult. The best method is to remove one or several leaves from a long shoot, make a 1 cm long cut along the stem where the leaf is removed and then bend the shoots 5 cm down the soil. The wound may be treated with a root-forming hormone. The soil must be kept wet and have a temperature of at least 20℃. P. racemosa is heat loving and especially suitable for a winter garden or greenhouse where the night temperature during winter is above 12℃, although, the plant will survive a few nights at lower temperatures. The plant easily becomes chlorotic so the leaves appear yellowish. This is due to lack of iron. It can be prevented by additional supply of e.g. iron-vitriol (ferrous sulfate heptahydrate).
Passiflora tarminiata grown out of doors on Madeira. Photo. Helene Heide-Jørgensen.
Passiflora tarminiana originates from the Andes Mountains (Venezuela to Peru), where it is often cultivated. Furthermore, it is introduced in many countries. In Hawaii it has become a threat towards local species. It is growing rapidly, resistant to diseases, and the fruits taste well. Therefore it is also cultivated out of doors in South European countries. It can self-pollinate, but since in nature it is pollinated by humming birds, it is usually necessary to hand pollinate the flowers in order to achieve good fruiting. The fruits are called ‘curuba’, ‘taxo’, and ‘banana passionfruit’. P. tarminiana has replaced the names P. mollisima and P. tripartita var. mollisima.
P. tarminiana is a climbing plant with 3-lobed leaves with dentate-serrate margins. The flowers hang solitary from the leaf axils. When fully open, the corolla is recurved. The light-green corolla tube is 6-8 cm long, and the pink flowers are 8-11 cm in diameter. The corona consists of one violet whorl of small white teeth. The ellipsoid fruit is yellow or orange and up to 14 cm long.
P. tarminiata grows naturally in the Andes Mountains between 2,000 and 2,700 m.a.s.l where it is usually cloudy with daily rain and temperatures varying year round between zero and 15℃. Therefore, in temperate countries it is best suited for greenhouse or winter garden, where, however, it only tolerates temperature above 30℃ for a short time. As in the species described above, the stem must be 2 m or longer before it produces flowers and a pot of minimum 35 cm diameter is required. Flowering may be promoted by removing the lower side branches. It flowers in late summer and autumn. Fresh seeds germinate after a week at 20℃. Propagation by cuttings is also possible.
Passiflora loefgrenii, Palmitos Park, Gran Canaria. The flowewrs are in the insect pollinated phase.
Passiflora loefgrenii originates from the region Ribeira in southeaster Brazil. The species was described in 1997 and arrived to Europe in 2000. Since it is frugal and beautiful with 12 cm large flowers, it is suitable for culture. It accepts temperatures down to 10℃. P. loefgreniiis a pronounced short-day plant, i.e. it flowers most willingly in the winter months when day length is shorter than 12 hours. It may flower already when it is about one meter high.
The leaves are entire end three-lobed. The solitary flowers are in principle hanging but the up to 20 cm long flower stalk bends upwards at the tip to present the flower in a more or less upright position. P. loefgrenii is from a pollination point of view particularly interesting since it is pollinated by both humming birds and relatively large bees of the genus Xylocopa (carpenter bees). The recurved strongly red-violet tepals and the long gynophore is an adaptation to bird pollination. In the first hours after the flower opens, both stamens and styles stay upright and in this phase the flower is pollinated by humming birds. Later on, the stamens and styles bend towards the corona, which has several whorls as typical for insect pollinated Passiflora species.
Passiflora colinvauxii with bilobed leaves.
Passiflora colinvauxii grown in a greenhouse. About flowering see ……
Four extrafloral nectaries on the abaxial leaf side.
Passiflora colinvauxii is remarkable in several ways. The species is endemic to the Galapagos Islands, where it even only occurs in a very limited area with Scalesia wood on the island of Santa Cruz.
It is a perennial climbing plant with thin stems and two-lobed leaves. The main nerve (vascular bundle) is very short in relation to the two lateral nerves of first order. The leaf lamina is equipped with nectaries secreting nectar on the lower side of the leaf and appear as light spots on the upper side (see photo).
In relation to the other species mentioned, the white and violet flowers are small with a diameter of 4-5 cm, but they excels by emitting an adventurous sweet scent to lure pollinators. The outer whorl of the corona is bicolored and the filaments have an almost angular knee in the middle, where the color changes from dark violet to white on the outermost part. Presumably, moths pollinate the flowers since bats (see ……..) can be excluded since they are not present on the Galapagos Islands.
The species is suitable for both winter garden and greenhouse, and in summer, it does well on a terrace as long as temperatures are above 10℃, but it has only recently been introduced to Europe and is probably not available in nurseries.
H. S. Heide-Jørgensen, marts 2011, translated May 2021.