The York Road site and Bird Sanctuary contain remnants of the original Eastern Suburbs Banksia Scrub, an endangered ecological community protected under State and Commonwealth legislation. 

Originally this scrubby vegetation extended across the Botany Sands to the southern shore of Botany Bay, but only a few small, isolated and disjunct fragments remain.

The swampy areas of the site originally would have been dominated by sedges, and the ridges of the Hawkesbury sandstone where seepage occurs dominated by wet heath, developing in locations into low open woodland with occasional tree cover.

Indigenous plant species that were present in the parklands in 2001 were documented by horticultural staff. Vegetation master plans were completed by Moriah College in 2002-03 for the York Road ESBS site. 

The total tree population across the four main open space precincts for the Centennial Parklands is over 15,000 individual trees. This total population includes over 115 different tree species representing at least 59 genera. The largest variety of specimens and species are concentrated within Centennial Park. Five key species account for over 90% of all trees present, accounting for the visual consistency of the parklands landscape.

Some introduced species including Maritime Pine (Pinus pinaster) and Golden Wreath Wattle (Acacia saligna) are invasive and require active management to control their proliferation. A suite of persistent herbaceous weeds is present in Centennial Park and Queens Park which are indicative of the long history of disruption and change to the natural soil and vegetation of the place.