We will start with a powerful one, the kind of plant that you want to be really careful with unless you want to engulf your whole garden as well as your house and your neighbor's as it will happily reach 10m (30 feet) long and even more! Yes indeed, Argyreia nervosa, the woolly morning-glory or elephant creeper, can turn into such a huge monster if you live in the tropics that you really have to think twice before growing it. A member of the Convolvulaceae family, the Argyreia genus is made up of some 90 different species, all woody climbers; but the A. nervosa species is by far the most common and well known. It comes from eastern India and is nowadays found wild in many tropical areas where it has become a quite troublesome invader like in Hawaii where it is called "baby Hawaiian wood-rose" and in Reunion where its name is ‘liane d'argent' which, as the numerous multilingual readers will guess, means ‘silver vine'. The silvery aspect of the leaves come from the woolly white hairs covering the underside, rather large heart-shaped leaves that can be 30 cm (one foot) across. The flowers are bells-shaped, pink with a darker throat and followed by the numerous seed pods which can have a long shelf life and used for house decoration or dry bouquets. Seeds have a reputation of mind-altering properties like seeds from several other species of the family.
After the giant guy we will turn toward the dwarf one of the family now. Ipomoea hederifolia belongs to the same botanical family but from a very large genus as there are no less than 600 recorded species among the Ipomoea genus. Compared to the previous creeper described, I. hederifolia has very reduced features; first it is an annual and will therefore not have time to reach serious heights. It can be seen scrambling over rocks and fallen limbs or twining on fences and will not go larger than one meter or two, if it has to make an effort in order to reach a sunny spot. Leaves are ovate, entire to 3- or 5-lobed. Flowers are tiny, bright red and come in abundance during short days (which in the tropics means less than 12 hours of light). I once stumbled upon a plant that was bearing orange corollas which seems quite unusual, after saving seeds I kept growing it years after years and the orange color is still there. This species originates from Tropical America and is nowadays very widespread and classified as weed in many countries especially in dry areas at lower elevations. It is often given as synonym Ipomoea coccinea but this one has entire leaves. Known as ‘scarlet creeper' in English-speaking countries it is called ‘amourette' on Reunion and ‘amourette à feuilles en Coeur in Mauritius' and is indeed quite lovely...
We will stick to the very same family and even stay within the same genus with another very widespread plant, Ipomoea pes-caprae. This one is an halophilous species which means it enjoys salted places, unsurprisingly it will be found growing on beaches where it will benefit of free space, sandy soil and seaspray as well as full sun which is actually what most people also seek when heading to the shore. This is a perennial plant which does not climb up but creeps, producing roots at every node and able to grow stems 10 to 20m (30 to 60 feet) long. The glossy green leaves are tough and obviously adapted to drought and strong sun, the bilobed blade reminds of the foot-print of goats hence the Latin name (pes-caprae means 'foot of goat'). The rather large flowers are pink-purple with a darker center and look quite nice on the sand but besides being pleasant to the eye the plant also plays an important part in keeping the sand in place thus avoiding wind to blow it away resulting in beach erosion. Known as ‘railroad vine', ‘beach morning glory' and in the Mascareignes as ‘patate à Durand' or ‘batatran' it is one of the most widespread plant on tropical beaches and a pretty strong one as it will resist temperatures of 40°C (104°C). The leaves have medicinal properties and used to treat rheumatism, fevers and diarrheas and are also used (at least on Reunion!) to relieve from spells.
After those steps on the hot sand we will turn towards land and after a short hike you may be intrigued by spherical fruits the size of a small melons, bearing marbles and stripes making them looking like some juicy watermelon hanging from trees. Alas, those belong to Lagenaria sphaerica which although being of the Cucurbitaceae family like the cantaloupe will not satisfy your thirst. One of the five species of the genus this plants comes from South Africa and is also named with the synonyms Luffa sphaerica, Lagenaria mascarena and Sphaerosicyos sphaericus. It is a dioceous species, producing long rambling or climbing stems several meters long, the leaves have five lobes which have a triangular shape. As many other plants of the same family, it produces tendrils which will help it to climb trees. The male flowers are held in clusters, with large white petals with green veins. Female flowers are solitary and produce those fruits with a thick rind that can only be used as decorative object as they can keep for long.
Here comes the last one, just at due time for dessert. The sweet granadilla, ‘grenadelle' in French, ‘granadilla' in Mexico, ‘pomme d'or' in Eastern Africa, all refer to Passiflora ligularis (synonyms are P. lowei, P. serratistipula). One of the over 650 species of passionflowers, it is one of the few commercially grown with large producing areas in Hawaii, Africa and Australia and of course Latin America. It grows wild in an area comprising central Mexico to Venezuela and Peru to Bolivia usually between 1000 and 3000 meters high (3300 to 10000 feet). A rather vigorous one, it has a woody base and can produce a stem 15m (45 feet) long if left unpruned. The leaves are large, heart-shaped and bright green with metallic shines. The flowers are pendulous, with a nice sweet perfume, sepals are white, petals are white with blue or pink shades, the corona filaments are on five to seven ranks, the first two series the same length as the petals, banded white and pale purple. The fruit itself is yellow or orange when ripe, the size of a goose's egg and full of sweet juicy flesh surrounding the numerous seeds. Propagation is quite easy either by sowing or cuttings.I hope you enjoyed this fifth promenade through the vines of Reunion Island. Be sure to not entangle your feet in all those scrambling stems and make time to come back for more!