Podranea ricasoliana (Tanf.) Sprague
Common names: Port St Johns creeper, pink trumpet vine (Eng.); Port St Johns klimop (Afr.)
Podranea ricasoliana, with its glossy foliage and abundance of attractive pink flowers, is a very showy plant, well known to many South African gardeners.
Podranea ricasoliana is a vigorous, woody, rambling, evergreen climber without tendrils. The leaves are compound and a deep glossy green. It sends up many tall strong stems — 3 to 5 m up to 10+ m high if left unchecked — that have long spreading branches with a graceful arching habit.
Large bunches of fragrant lilac-pink, trumpet-shaped, foxglove-like flowers are produced all summer long (November to March). The flowers are carried at the branch tips of the new growth, and are held above the foliage. The flowers terminate a branch, After flowering new side branches develop behind the spent flowers. The fruit is a long, narrow, straight, flattened capsule. The seeds are brown, ovate and flat, in a large rectangular papery wing. It tends not to produce many fertile seeds.
According to the Red List of South African Plants, Podranea ricasoliana is assessed as Vulnerable (VU). It is a highly localized endemic found in a restricted habitat that is not protected. Although locally common its habitat is at risk of degradation by subsistence farming, wood harvesting, invasive alien plants and fires.
Distribution and habitat
The genus Podranea contains Podranea ricasoliana, found at the mouth of the Mzimvubu River at Port St Johns, roughly half-way between East London and Durban on the Eastern Cape coast; and Podranea brycei, the Zimbabwe creeper, which has been collected from the ruins of Great Zimbabwe near Musvingo in Zimbabwe, and from the surroundings of Nova Sofala, on the Mozambique coast south of Beira. These two species differ only in the hairiness of the flowers and the size of the leaves. As it is virtually impossible to tell them apart when seen growing together many botanists regard them as the same species.
Many South African botanists suspect that this climber may not be indigenous to southern Africa and that it was introduced here by slave traders. All the sites where both Podranea ricasoliana and Podranea brycei are found have ancient connections with slave traders who frequented the eastern coast of Africa long before the 1600s. It has become such a widely grown garden plant in all the warmer parts of the world that it may prove difficult to find its real origin.
Derivation of name and historical aspects
Podranea ricasoliana is a member of the Bignoniaceae, a family of ±109 genera, mainly trees, lianes and shrubs from mostly tropical regions particularly in South America. There are 8 southern African genera, plus 2 that have become naturalised. The member of this family most well known to South Africans is the jacaranda, Jacaranda mimosifolia. This tree is not indigenous to Africa; it comes from South America, but has become naturalised in the warmer parts of South Africa. Indigenous species include the Cape honeysuckle, Tecomaria capensis and the sausage tree, Kigelia africana.
The name Podranea is an anagram of Pandorea, a closely related Australian genus, in which Podranea was first classified. Pandora means all-gifted. She was the first woman of Greek mythology and was given the box that contained all man's ills. When she opened it, they all flew out.
The flowers are often visited by carpenter bees (Xylocopa species).
The Port St Johns creeper is well-known to gardeners in southern Africa, Mediterranean countries, California, Florida, Australia and Asia, and has become a popular container plant in Europe, where it is over-wintered in heated greenhouses. It was grown in the early 1800's in British conservatories, and La Mortola Botanic Garden near Monaco.
In South Africa, White's Nursery in Durban was propagating it in the early 1900s, and many of the South African plantings can trace their origin to this nursery. Visitors to the World Expo in Seville, Spain, were sheltered from the blazing Andalusian sun by a kilometres-long pergola overgrown by Port St Johns creeper trailing down from hydroponic troughs on top of the beams. Restaurants and hotels on the French Riviera, the Balearic Isles and coastal Italian cities like Sorrento grow Podranea ricasoliana in large clay pots, training the graceful branches in patterns up their terra cotta walls.
Growing Podranea ricasoliana
Podranea ricasoliana is fast-growing and easy in cultivation. It does best in full sun, in nutrient-rich, well-drained soil and benefits greatly from regular applications of well-rotted compost and plenty of water in summer. An established plant is tolerant of heat, strong sunlight, wind and periods of drought. It is tolerant of light frost and should survive a winter minimum of -7ºC / 20ºF (zone 9) although it is better suited to frost-free gardens. Young plants require protection from frost, and if an established plant is cut down by frost, it should resprout in the spring. Because it is so vigorous and so fast it can get a bit out of control and may grow into gutters and roof overhangs and into trees, particularly in subtropical regions. It will need pruning to be kept neat; to keep it down to shrub size it should be pruned back hard every year. Pruning will also improve flowering. The best time for pruning is in winter or early spring just before new growth commences. It is known to sprout where prunings have been thrown, and it is an invasive, garden-escape in parts of Queensland and New South Wales in Australia and in New Zealand.
This is an excellent plant for arbors, pergolas and carports and is a valuable shade-giving plant in a hot climate. It is ideal for an informal hedge or planted against a wall or a fence to create a screen. It is a useful rambling ground cover for an embankment as the stems root wherever they touch the soil, forming large, swollen water- and soil-holding root clumps. It is suitable for the coastal garden. It looks good in a large container and is a candidate for espalier and can be pruned and trained into a weeping standard. It has no tendrils, so it has to be tied to supports. Port St Johns creeper mixes with Bauhinia galpinii, Plumbago auriculata, and Tecomaria capensis, providing an interesting intermingling of colours. It is not a good cut flower as the flowers drop quite soon after cutting.
This is not generally a pest-ridden plant. You may find tip/twig wilters, also called black stinkbugs or dahlia bugs (Anoplocnemis curvipes), on young shoots, and aphids on the flower buds.
Propagation is by seed, cuttings or layering.
Although a proportion of the seed may be infertile, about 50% should germinate. Seed should be sown in spring or during summer, in a well-drained seedling mix, and need only be covered lightly with the sowing mix, clean coarse sand or milled bark to stop it from blowing away. The trays should be kept moist in a warm but shaded position. Germination should occur in 3-4 weeks and the seedlings potted up after the first pair of true leaves have developed.
Semi-ripe hardwood and/or hardwood cuttings can be taken in spring or during summer. They do not require mist or bottom heat to root, but are best in a covered frame in a well aerated medium e.g. equal parts peat and polystyrene. Rooting period is 6 weeks, with another 6 weeks weaning period.
Podranea ricasoliana can also be propagated by means of layering, or by removing side branches that have rooted by themselves. To encourage Podranea to root by layering, take a low growing stem, lay it along the ground without breaking it off the mother plant, bend the tip to a vertical position, stake it in place and bury or cover the part that is touching the ground with soil. The roots should form at the sharp bend, but inflicting a wound on the lower bent side may also help. Keep the soil moist and remove when a sizeable root ball has developed.
Christien Malan & Alice Notten
Kirstenbosch National Botanical Garden
Plant Type: Climber, Scrambler
SA Distribution: Eastern Cape, KwaZulu-Natal
Soil type: Sandy, Loam
Flowering season: Late Summer, Autumn
PH: Acid, Neutral
Flower colour: Pink, Mauve/Lilac
Aspect: Full Sun
Gardening skill: Easy