The amount and value of landscape work undertaken in the U.K. has increased significantly. All sectors of the industry have expanded to meet this demand: designers, nursery stock suppliers, contractors and others. It was soon appreciated that creating successful landscapes depended on mutual co-operation within the industry that resulted in the formation of the Joint Council for Landscape Industries (JCLI).

One area of mutual interest to designer, nursery supplier and contractor is the supply of plants. The need to obtain good plants of the required species and sizes has long since been recognised. An early task of the JCLI was to draw up select lists of trees, shrubs and other plants which were considered most suitable for landscape planting. These lists, approved by representatives of all members of the industry, have been continuously updated by the Committee on Plant Supply and Establishment (CPSE), a technical sub-committee of the JCLI. The current revisions, Trees and Shrubs for Landscape Planting (1997) and Herbaceous Perennials for Landscape Planting (1994) supersede earlier versions.

Those working within the industry are not only interested in the approved short list of species recommended for landscape work but also in the range of sizes and conditions in which these plants can be obtained. For a number of years the British Standards Institution has produced a number of standards setting out criteria for the supply of plants. However in the early 1990's, there was sufficient concern about the profitability of the wholesale nursery stock industry for the Horticultural Trades Association to commission a report (Developing the Amenity Market, 1996). One of the deficiencies identified in this report was the variable and inaccurate specification of plant sizes and conditions and the effect this was having on the wholesale nursery stock sector. Lack of rigour and use of accepted terms and specifications was providing room for abuse in tendering. This was resulting not only in reduction of price, profit and performance but also frustration for all sectors of the industry. It was also recognised that changes in production techniques were happening rapidly and this information was not being disseminated throughout the industry and informing the development of improved standards and specifications. The report recommended the need for a National Plant Specification, combining the disparate information on this subject, which could be used as an industry standard and form the basis of fair trading throughout the industry.

The production of the National Plant Specification acknowledges and responds to the following:

1. British Standards contain much useful information, however the rate of change occurring in production practices in the industry is so rapid that that standards are quite quickly becoming out of date.

2. Changes within plant production have resulted in the production of specialist standards and these need to be incorporated into the industry wide documentation.

3. Plants are being bought and traded throughout Europe and grades and standards across the continent ought to respond to this.

4. Current standards provide general information on grades and conditions of product. Specific information on grades and conditions for a range of typical landscape plants would provide more particularly useful information.

The essential problem of providing grades and standards for such variable products as plants has been a difficulty for all those providing specifications for plants. Even within a species, plants will vary both genetically and physiologically. In addition the same plant will vary with age and season. This document recognises these limitations. It is the first attempt to bring together information from a wide range of sources. It is accepted that it is neither complete nor absolute. However, it will provide the basis for a centralised and developing body of information on plant specification which is accepted throughout the industry which is regularly revised and updated to reflect not only changes of production within the industry but also improvements to the means of grading and specifying plants.

It is important to realise that plants are an infinitely variable product. It is impossible to list all the various sizes and conditions in which plants can be grown and it is accepted that excellent plants are probably available which do not conform to this specification. However, the specifications listed in Helios give an extensive range of appropriate specifications for the plant types based on current production. Highlighted within these lists are those identified by wholesale nursery suppliers as being the most typical ones used in the majority of landscape projects (Growers' Version). It is part of the philosophy of those who produced this resource and the JCLI to regular updates. By this means it is hoped to continue and improve the dialogue between those producing the plants and those specifying them. Each new release will reflect not only new production techniques and practice but also improvements in the methods of specifying these products. Helios represents the beginning of this process, not the end of it.