It is one of the unwritten rules of life (and of gardening) that the grass is always greener on the other side of the fence. That maxim manifests itself in some very uncomfortable ways in our private lives, but it also causes pain in the garden. I am sure Aucklanders, who can grow an incredible range of plants, are upset that many cold-requiring plants will not flourish there. I have seen the saddest flowering cherries and hardy Rhododendrons sulking away in Auckland gardens, when far more appropriate plants would grow much better.
In reverse, those who garden in the far south would love to be able to grow many of the subtropical plants that Aucklanders take for granted, willingly swapping their swedes and turnips for some bougainvilleas and orchids growing in the garden.
We are sort of stuck in the middle here. Some plants will not grow because our climate is not cold enough – I despair of ever successfully flowering that doyen of Fritillaries, Fritillaria imperialis despite many attempts – and our frosts mean we have to be very careful about providing any tender plants with special shelter.
For my own part, there is one group of plants I would love to be able to grow with the ease that those further north can – the shrubby Hibiscus. Whenever we go on a summer break to northern climes I rush around with my camera, snapping the glorious silken flowers these flamboyant plants bear each year, insanely jealous, recognising that growing them around my place is just a pipedream. They are very frost tender and in Wairarapa they need to be placed against a north-facing wall, preferably in full sun, and in well-drained soil. None of the many varieties can cope with poor drainage, so clay soils are out too. If you are stuck with sticky soil, and you have a warm spot for one of these beauties, I think it probably pays to invest in a nice big pot and some free-draining potting mix.
We took this step about ten years ago, when one of the boys became interested in growing some ‘indoor’ Hibiscus – they are sold that way but they will be temporary Hibiscus if grown inside for very long. We bought a couple of these small flowered hybrids and potted them into large earthenware containers on the patio in an east-facing spot. They did very well for the first few years, but their performance has fallen away – the yellow one is very spindly and the red one has gone to the great garden in the sky.
To grow Hibiscus successfully in pots you need to start feeding them as once they are established, as Hibiscus are hungry feeders. The easiest way to provide them with nourishment is a good application of some slow release tree and shrub fertiliser in early summer. Hibiscus only flower on new wood so it is good to clean out the old branches each winter and let the plant renew itself. You can be tough with the pruning – if the plants are starting to get a bit leggy and woody you can cut them back very hard. Within a year they will have bounced back with a new framework of growth of and more crops of flowers. Most varieties branch near to ground level and make attractively thick growth. If you have a mind to, Hibiscus can be trained to make wonderful espaliered shrubs, an especially good way to grow them in our climate as they are well suited to growing up under the eaves of a north-facing wall.