Mawarra, the residence erected and the garden laid out by c.1928-32 to a design of Edna Walling and rockwork constructed by Eric Hammond, and carefully maintained with few changes of ownership, is of State cultural significance:
- As one of the undoubted masterpieces of Edna Walling's landscaping (an opinion shared by Walling herself), a bold and confident essay which blends her architectural or formal style with softer woodland planting; Walling had by this date developed an enviable reputation as Victoria's (and one of Australia's) foremost landscape designers and Mawarra represents the peak of her early formal style, which increasingly gave way to a less formal style with greater use of Australian plants;
- for the design, which is a brilliant blend of accomplished workmanship, confident handling of the steeply sloping site by use of terracing and steps, technically difficult elements (such as the curved steps) and careful planting (ranging from large trees to the detailed planting of bulbs);
- for the retention of buildings, structures and works from the Walling design and first period of development; these include the original section of the residence, children's playhouse, summerhouse, stone walls, steps, paths and pools;
- for the survival of considerable planting from the early development of Walling's plan for the garden; this includes a fine collection of trees, exotic shrubs and bulbs,
- for its aesthetic qualities; these are derived from the sense of expectation inherent in the long drive, the maturity of the original planting, seasonal contrasts through the use of deciduous plants, the strong axis with steps leading to the pond, the contrast between dense shrubberies and open woodland, the use of straight paths which permit long and controlled vistas and careful planting combinations;
- for the high level of intactness of the garden, the survival of Walling's plan which enables this intactness to be assessed and the relatively high level of maintenance which has continued since the initial development of the garden;
- for its setting in the hills, which permits wide range of cool climate plants to be grown, and which assists in an understanding of a wave of development of the Dandenong Ranges (following the period of land selection in the 1890s).
Probable national significance has not been assessed as part of this classification report.