Franchesca Watson guides us through achieving the enduring appeal of a hanging garden
You see it in nature, cascading over cliffs and dramatic slopes. The magic is that the plants change and turn to present their leaves more gracefully – and you would be surprised by the variety of species that are perfectly happy to hang. We imagine it is otherworldly and exotic hence our enduring fascination with the Hanging Gardens of Babylon, which I believe did indeed exist – why ever wouldn’t they have?
We can use this quality to great advantage very simply when we garden. Think of all those gorgeous balcony planters and hanging baskets that one sees decorating cities in Europe, with tumbling Pelargoniums (hybrids of our South African plants) and toppling Petunias. Closer to home think of the pergolas and carports so commonly planted with bougainvilleas and how prolific the plant becomes when it reaches the top of the pergola or support structure and begins to spread out and flop over the edges.
You do not have to use creepers. Ordinary shrubs will cascade happily – it is only the very strict ones such as Camellias, Coleonemas and hybrid tea roses that only want to stretch upwards. There are many, many more that will grow up first and then stretch outwards and downwards. I have seen Searsia crenata do this beautifully, Ceratostigma, Bauhinia galpinii, and Vitex do it wonderfully, as do plumbago, Carissas, and many bushy succulents such as Senecio ficoides. The list is endless as plants are programmed to use any advantages they get, the most important being good soil and ample room for their roots to ramble and foliage to flourish.
The trick is to create areas of the garden where there is space beneath the point of planting, such as sloping banks or berms, terraced planting and walls with planting spaces in or on top of them. Even ubiquitous retaining block walls can be wonderfully and permanently greened if the blocks are filled with good quality soil, installed at an angle that allows planting space and then planted with a fair-sized, long-lived plant such as Barleria. Small, short-lived groundcovers such as Sutera are fatal.
It is an incredibly exciting way of displaying plants – a bit like a drone shot from above, turned sideways so you can view the plants straight on. A bird’s-eye view of the mosaic of the leaves is displayed so that one can see it vertically. If you have ever done a canopy walk, you would have seen how the trees fit together like a jigsaw puzzle. This happens when plants hang too. Whether one is working with scaled up plants such as the larger-than-life Philodendron selloum and Streptosolen varieties, or smaller more dainty species such as ferns or Iris japonica and Streptocarpus varieties, they all develop a new character when planted to hang, revelling in the new way they can interact with each other. As long as they have their roots well attached in a good, expansive soil system, they will fill you with delight.