Social climbers

Climbers are a plant group that are often consigned to the “cover it up” category but can add colour and interest to a garden when other plants may not be doing so well – and are an easy way of camouflaging a plain or not-so-pretty fence or wall.

A climbing rose does a good job of softening and adding some colour to a wall in this Tauranga garden. Photo: Sandra Simpson

Vigna caracalla (snail bean or snail flower) is a scented, perennial climber that blooms in summer. A member of the legume family, Vigna caracalla grows like a scarlet runner bean (but is entirely ornamental) and will happily drape across other plants if it can reach them.

Vigna caracalla is a perennial climber with sweet-scented flowers. Photo: Sandra Simpson

The unusual curled flowers, which provide the plant’s common name, have a delightful perfume reminiscent of a hyacinth and are followed by bean-like pods. You can try growing your own from these seeds, but they don’t always take. King’s Seeds at Katikati can supply guaranteed seed.

Cut the plant back to ground level when it’s finished and wait for it to shoot back next season.

Tecomanthe (trumpet-vine) climbers are vigorous tropical plants, found naturally from Malaysia to New Zealand, with our one native variety being Tecomanthe speciosa from Three Kings Islands.

Botanists found one specimen in 1946 and all the plants we have today have descended from this plant. It needs a strong support, but has glossy leaves and attractive clusters of creamy tubular flowers in spring.

Te Puna Quarry Park has its pink-flowered New Guinea cousin, Tecomanthe venusta, twining up a pine tree in its orchid area with the flowers lower down on the vine as the climber blooms on old wood.

Tecomanthe venusta at Te Puna Quarry Park. Photo: Sandra Simpson

Clematis, like wisteria (read an earlier post about wisteria here), are a real signifier of spring. Some people find them tricky to grow – I was struggling with ‘ Mrs Cholmondeley’ until advised to bury the neck of the plant deeper and now she performs well for me every year.

Clematis vitacella ‘Kermasina’ seen at Alnwick Castle garden in Northumbria, England. Photo: Sandra Simpson

The entry for Clematis viticella ‘Kermesina’ at Vibrant Earth, a New Zealand wholesaler, reveals that the viticellas are “extremely cold hardy and more wind tolerant than large-flower types” and are resistant to stem-wilt (my problem with ‘Mrs Cholmondeley’). Viticellas tend to be single stemmed and spindly growing in the first year or two.

How about this beauty? Clematis ‘Viennetta’ is a double-flowered variety with a long blooming period period, up to 5 months in the northern hemisphere. Unfortunately, it doesn’t appear to be available in New Zealand.

Clematis ‘Viennetta’. Photo: Sandra Simpson

Creepers and climbers can also be positioned to scramble through and across other plants, adding extra seasonal interest – when one plant’s in full swing the other may be less obvious, later reversing positions.

The Scottish flame flower (Tropaeolum speciosum) scrambles across one of the many old yew trees at Levens Hall Gardens in Cumbria, England. The scarlet flowers are followed by blue berries. Photo: Sandra Simpson

The photo above is truly an instance of right place, right plant. In New Zealand Tropaeolum speciosum is known as the Chilean flame flower and considered a weed! Read how to eradicate it here.

Our native plants: Pennantia baylisiana

Pennantia baylisiana once held the dubious title of being the rarest plant in the world with only one female tree in its native Three Kings Islands. This dire state of affairs began to be remedied in 1945 when Professor Geoff Baylis (1913-2003) of Otago University took six cuttings from the (then) goat-ravaged islands to be grown on at the Government research station at Mt Albert. Three survived and more cuttings were taken from them and then, glory be, one plant spontaneously produced female and male flowers! It is thought that the one surviving tree, while “fundamentally female”, also has some “low-level” male characteristics.

Pennantia baylisiana, complete with berries, photographed in Wellington Botanic Gardens last weekend. Apparently the berries ripen to blue. There is also a specimen growing in the Auckland Regional Botanic Gardens. Photo: Sandra Simpson

The Terrain website says: “The single tree known in the wild grows on a scree slope on the northern face of Great Island in the Three Kings group off Cape Reinga, New Zealand. It is still alive today some 65 years later, and has not produced any seedlings on the islands. Forty years after the Pennantia was found Ross Beever (1946-2010), a scientist with Landcare Research, tried to see if he could induce it to produce seed. He was successful and the resulting seedlings have proved to be more fertile than their mother.”

Oratia Native Plant Nursery which assisted Ross in his project, donates all proceeds from the sale of Pennantias to help fund botanical research and to minimise the risk of extinction of other species.

It should be noted that Professor Baylis took some drastic action to try and save the tree (Journal of the Royal New Zealand Institute of Horticulture, Vol. 2, No. 1, March 1997, pp. 12–13). Read the entire article here.

“Propagating this lone and sterile tree, not in the best of health because of insect damage, seemed urgent. There was a detachable shoot at its base, which took root in a damp sheltered place in my Dunedin garden and is now very like its parent with four slender trunks. But its canopy trimmed by occasional frost rather than repeated salty gales is taller (7m),” Prof. Baylis wrote.

“While I was unsure that this shoot had really rooted, I was worried by failure both at the Plant Diseases Division at Mt Albert and at Duncan and Davies, New Plymouth, to strike cuttings from the crown. I asked George Smith, the chief propagator at New Plymouth, what I might do to provide better cuttings. ‘Cut the tree down,’ he said, and while I shuddered at the thought, he explained that he was confident about rooting shoots from the stump. But would there be any? Well, the tree had four trunks so I dared to sever one. A year later, the shoots were there. The naval launch on which I was a guest gave them a quick passage to New Plymouth, which happened to be its next port, and Mr Smith soon placed the survival of [the tree] beyond doubt.”

Brave man!

In 2010 New Zealand scientists took 1600 seeds back to the islands to plant. Read more here. The tree’s status today is described as ‘nationally critical’.

Lawrie Metcalfe in The Cultivation of NZ Trees and Shrubs (Raupo, 2011) says in the garden P. baylisiana will grow to 3-4m. “Where a large-leafed tree is required for effect, this magnificent foliage plant is ideal.”

A cross of P. baylisiana with P. carymbosa seen growing at Otari Wilton’s Bush in Wellington. The hybrid has been named Otari Debut. Photo: Sandra Simpson

P. corymbosa (kaikomako) is a relatively common forest tree of mainland New Zealand. Apparently it hybridises quite easily with P. baylisiana. P. cunninghamii (brown beech) is a rainforest tree of eastern Australia. The final tree in the family is P. endlicheri, native to Norfolk Island, once thought to be identical to P. baylisiana but now proved not to be.

The same day Prof. Baylis found P. baylisiana, he also came across the woody vine, Tecomanthe speciosa and managed to save that from extinction too, but that’s another story.