The rapid infestation of the prickly pear cactus, Opuntia stricta, led to abandoned properties and surrendered large pastoral leases in affected areas of Queensland.

The nationalist sentiment of the Federation era influenced a wider appreciation of Australia's flora and fauna, with native plants and animals appropriated as patriotic symbols in architecture and the decorative arts and crafts.

While part of the horticultural purpose of these places was to provide public spaces of ornament and beauty for recreation and education, research and experimentation into the utilitarian qualities of plants were also major functions.

While beauty and climatic suitability were important considerations, Gordon also consciously chose particular inland plants for conservation purposes, because of their vulnerability in their natural habitat from land clearing and grazing practices.

Transport links were improved by the extension of the branch of the Western railway line from Dalby to its terminus, the newly surveyed town of Glenmorgan, seven kilometres south-east of Myall Park in 1931.

In 1941 the first garden plantings commenced, including needlewood (Hakea leucoptera), scarlet bottlebrush (Callistemon macropunctatus) and silver cassia (Senna artemisiodes) and species of Acacias and Eucalypts.

[1][20] Gordon's interest brought him into contact and correspondence with fellow native plant (and wildlife) enthusiasts from across Australia, including botanists, horticulturalists and naturalists.

Another early contact was George Althofer, who with his brother Peter, established Nindethana, one of Australia's earliest commercial nurseries dedicated to native flora at Dripstone, New South Wales.

[1][30][31] In 1951, Gordon employed English horticulturalist Len Miller, an assisted migrant soldier who worked as a gardener for Bristol City Council, providing accommodation for him and his wife Ivy in a new timber house (given the name Terpersie) at Myall Park.

As officer-in-charge at the Wail Forest Commission Nursery in Western Victoria (1946–54), Gray had pioneered arid land revegetation through provenance seed harvesting and native plant supply.

The nursery was built by Harry Howe, with the assistance of cabinetmaker Bill Dunmall, who fitted out the vermin proof seed storage room with silky oak cabinet drawers.

Around this time a large single room, lined with tall cupboards and work benches was constructed at the Gordon family residence house, to provide an art space for Dorothy and to store herbarium specimens.

By the time Gray left Myall Park in 1957, he (like his predecessor Len Miller) had made a major and important contribution to the development of the garden and herbarium.

Albert Robinson replaced Alf Gray and worked for ten years in the garden, continuing propagation projects and cultivating existing plants.

The "grandiose scale" of Gordon's efforts to conserve and grow inland native plants had been acknowledged by the mid-1950s [51] and visitors became increasingly common at Myall Park.

In addition to visits from specialist interest groups, naturalists, botanists and scientists from institutions like the Queensland Herbarium, experts from other disciplines also conducted research at Myall Park, including world bee authority Dr Charles Michener.

Increased environmental awareness, availability of native plants in nurseries, architectural fashions for bushland settings for houses and garden designs reflective of natural Australian environments all contributed to this popularity.

The Society for Growing Australian Plants (of which David Gordon was a life member) was established in Melbourne in 1957 and rapidly grew to become a national body with state branches.

This renewed activity coincided with the increased recognition of Myall Park as a significant botanic garden in ex-situ conservation of rare and endangered plants.

Following her death in a car accident in 1985, a book of this work, Australian Wildflower Paintings, with botanical notes by Dave Gordon was published in 1988, with the assistance of a Bicentennial grant and Meandarra Arts Council.

[1][58] Following Australian Government grant funding in 1995, an art gallery designed by Brisbane architect Brian Donovan was opened, housing a permanent display of Dorothy Gordon's original botanical watercolours.

[1] A looping gravel drive circulates through the site, entering from the eastern side of the property and broadly follows the edges of the garden, as laid out by David Gordon.

[1] The gallery and toilets (1995) and the old sawmill shed (mostly reconstructed) near the entry of the park are not of cultural heritage significance although they are important components in the current day activities of the garden.

[1] Near the eastern edge of the garden, south-east of the gallery is the cluster of buildings comprising Terpersie Cottage (former nurseryman's residence), the nursery, the garage, and the single men's quarters.

[1] To the north-east of the garage is the single men's quarters, an L-shaped single-storey low-set timber building with a chamferboard exterior and a gable roof clad with corrugated metal sheets.

[1] To the south of this group is Avochie Cottage, a single-storey low-set timber residence with a chamferboard exterior and a multi-gabled roof clad with corrugated metal sheets.

[1] Myall Park Botanic Garden has fulfilled many of the traditional functions associated with botanical gardens since the 1940s; increasing horticultural and scientific knowledge about flora, sharing information, seed and plant stock with like-minded institutions, experts and enthusiasts, providing an attractive and educational venue for public recreation (since 1988); and in some instances, providing plant material to nurseries and the public.

[1] This building was provided for on-property workers, as distinct from the shearers' quarters located adjacent to the shearing shed several kilometres from the homestead and garden.

[1] The importance of the aesthetic experience of Myall Park Botanic Garden has been demonstrated over many years in its popularity as a tourist destination and its inspiration for artists, writers, photographers, and musicians.

The successful creation of the hybrid Grevillea 'Robyn Gordon', encouraged through a deliberate planting process, was an important technical achievement in the field of Australian floral horticulture in the 1960s.