In the words of its longest serving president, Geoffrey Jellicoe, “It is only in the present century that the collective landscape has emerged as a social necessity.

From the 1950s to the 1980s, the public sector (particularly local authorities) was the largest employer of landscape architects, with a minority working in private practice.

In the 21st century, and especially following public spending reforms post-2009, a greater majority of landscape architects are employed in the private sector.

The development of the ancient art is analysed by Geoffrey Jellicoe, in The Landscape of Man, and by Norman T. Newton in Design on the land.

[7] Newton, defines ‘landscape architecture’ as the art ‘of arranging land, together with the spaces and objects upon it, for safe, efficient, healthful, pleasant human use’ and writes that ‘the ancient art became a new profession officially, when in 1863 the title Landscape Architect was first used by the state-appointed Board of Central Park Commissioners in New York City.

Nesfield described himself as a landscape architect on his submitted plan for the garden of Britain's most famous residence, Buckingham Palace.

It was Olmsted's long and brilliant career that led to it becoming famous and being associated with public projects: for parks, greenways, open space systems and urban design.

When working on the Dunfermline Competition for Pittencrieff Park, Thomas Mawson and Patrick Geddes had been the first two men to use the term ‘landscape architect’ in the sense established by Frederick Law Olmsted's office.

She told Tony Aldous, who was commissioned by the LI to write a book on its history, that ‘Most of the people who started the institute were only doing private gardens, you must remember’.

The Objects of the ILA were defined in Clause 2 of its first Constitution (drafted by Gilbert Henry Jenkins): ‘The Institute shall be formed to promote the study and general advancement of the Art of Landscape Architecture in all its branches, and to serve as a medium of friendly intercourse between the members and others practising or interested in the Art’.

In Clause 3, ten Methods of Achievement were set out: Establish suitable headquarters; Arrange lectures; Prepare sets of lantern slides; Promote the publication of a Journal; Arrange periodical exhibitions; Found a Library; Educate the public in the Art of Landscape Architecture; Secure the establishment of one or more Training Centres; Organise visits to good examples of Landscape Architecture; Hold Conferences with other Societies who can assist in promoting the Art of Landscape Architecture.

Some of the garden designers (including Stanley Hart[21]) left because of the restriction that members of the new institute must not earn money from trade.

He visited the US in 1942 and, like Adams, was impressed by the range of work undertaken by members of the American Society of Landscape Architects (ASLA).

To become a professional member, however, candidates must first have completed an LI-accredited university course or alternatively be assessed as a special case for admission as an Associate.

Following this they proceed along the Pathway to Chartership (P2C), a mentored and supervised programme of learning which culminates in an interview with two examiners who are senior members of the profession, once the candidate has attained an agreed level of competency.

The activities of the LI include maintaining a membership database, member communications, newsletters, the Journal, CPD, professional examinations, enforcing a Code of Practice, policy and technical outputs, and advocacy.

Entitled I want to be a Landscape Architect, it focused on increasing the number of postgraduate and undergraduate students taking LI accredited courses.