PUBLICATIONS

Issue 41 - Spring 2007

In Praise of Exotics

I don’t know whether it’s moribund nationalism or woolly-headed ecology, but the notion that the planting of ‘native’ species of trees and shrubs carries with it an inherent virtue continues to influence and intimidate the majority of Irish designers and landscapers.  This is seldom a thought out position; it is normally an article of faith based on the perceived wisdom of other experts.

In order to analyse this peculiar phenomena the first principle to establish is what is meant by the term ‘native plant’. Normally, in the Irish context, we mean species that have established themselves since the end of the last ice age (about 10,000 years ago), before the land bridge with Britain was broken, and without the aid of humans. This can be a useful, if limited, classification of a group of plants which have successfully adapted to a set of environmental conditions and which will thrive so long as these conditions remain stable. But does the fact that a particular species happened to find itself growing in an Ireland that became an island instil within it a particular merit which sets it apart from all other plants?

There are, of course, situations in which the preservation of an indigenous environment is highly desirable. Unique ecosystems such as Madagascar and La Gomera in the Canary Islands are examples of self-contained regions that have produced plants whose integrity would be severely compromised by the introduction of alien species. But this is not the case in Ireland.  The vast majority of the plants common to this island swept in from other lands and, finding it an equitable climate, happily settled in and over time established themselves as dominant species. Later, much later, other species were deliberately introduced and not surprisingly often filled an environmental niche better than the original plants.

This is manifestly obvious in the case of coastal trees and shrubs.  The success of nearly any seaside planting relies more than anything else on creating effective shelter. This can mean simple filtering in which case ‘native’ wind and salt tolerant  trees such as Alder, Ash and Willow will suffice, but more ambitious planting schemes call for more effective (usually evergreen) screening. A successful shelterbelt must tolerate extreme salt laden wind of course, but, just as important, it must adapt to a great diversity of soil types, from the heavy peaty soils of the Southwest to the rocky soils of the West Coast to the sandy soils of the Southeast. No single plant can meet all these criteria, but the list of trees and shrubs that are able to tolerate these varying conditions reads like socially inclusive new Ireland: Pinus radiata, P. muricata, and P. contorta, all from the Northwest coast of the U.S. as is Cupressus macrocarpa; Pinus thunbergii (Japan); Pinus wallichiana (Himalayas); Escallonia rubra macrantha (Chile); Fuchsia magellanica (Chile – I particularly like the fact that the blow-in Fuchsia has been selected as the symbol to represent West Cork); Griselinia litoralis (New Zealand); and Olearia macrodonta and traversii (also New Zealand). Many other plants have been successfully employed as shelterbelts including Quercus ilex, Elaeagnus x ebbingei, Pittosporum tenuifolium and Phormium tenax, and the one quality that they all share is that none of them has its origins in this fair land. In fact, very few trees and shrubs used as seaside shelterbelts can claim Irish roots.
Furthermore, the great majority of ornamental plants used in coastal gardens are of distinctly foreign origin. Examples include Agapanthus, Cistus, Euryops, Grevillea, Hebes, Hydrangea macrantha, Osteospermem, Pittosporum, Santolina, Brachyglottis, and a host of other aliens. Limitations are determined by soil and climate, not by country of origin. 

Several unremarkable species including Salix hibernica, Ulex europaeus ‘Strictus’ and Sorbus hibernica, have evolved and established themselves here as true ‘natives’ (as has the more desirable Taxus baccaa ‘Fastigiata’), but it can be reasonably argued that Ireland has not provided a hotbed of unique woody plants. However, one could make a claim for Ireland as the nursery of many cultivars of alien or exotic flora. Solanum crispim ‘Glasnevin’,  Griselinia  litt. ‘Bantry Bay’, Schizostylis coccinea ‘Mrs. Hegarty’, and Myrtus apiculata ‘Glanleam Gold’ are all popular examples of exotic plants which have performed so well in the Irish context that they have developed forms which have become fashionable coastal as well as urban landscape subjects.

It is, of course, not so simple as all this. Considerations such as texture, meaning, and context can often demand a particular choice of subjects, and sometimes that means going native. But to arbitrarily limit ourselves to ‘native’ plants is akin to limiting ourselves to only a few colours of a palette. Design is intervention. Even the most naturalistic and sympathetic concept is an intrusion on the environment. At the risk of sounding too ‘preachy’, I would hope that any design would consider all the tools available and choose the most appropriate without prejudice.

Bill Chase

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