Plants grow in communities associated with particular soil and climatic conditions.
The interaction between soils, topography, and climate determines the nature of the vegetation. Hawkesbury River floodplain. Tall trees included Broad-leaved Apple, Angophora subvelutina, and Forest Red Gum, Eucalyptus tereticornis. In places, vines such as Stephania japonica, Clematis glycinoides and Pandorea pandorana formed thick tangles amongst shrubs of Hymenanthera dentata, Bursaria spinosa and Clerodendrum tomentosum. These areas were rapidly cleared to provide the first rich agricultural soils for the colony.