Cooper Park is roughly composed of two remnant vegetation areas:
It is difficult to identify remnant vegetation in Cooper Park due to the extensive planting of native species which occured in the 1930s and 1970s. Over 500 native trees, shrubs and grasses were planted in 1974-76 when a three-year revegetation and regeneration scheme was undertaken.
Rose Bay supported dune scrub vegetation with fragmented stands of Paper-bark swamp. the dominant species are assumed to be Leptospermum laevigatum (Coast Tea-tree), Banksia serrata (Old Man Banksia), Banksia ericifolia (Heath Banksia), various Casuarina sp. (She-oaks) and Melaleuca quinquenervia (Broad-leaved Paper-bark).
Most of this vegetation type has been destroyed. The Royal Sydney Golf Course contains small remnants of vegetation including the north-east corner of Paper-barks.
Taller eucalypt forest (Tall Open Forest) to a height of 25 metres would be found here. Typical species includes Eucalyptus piperita ssp. piperita (Sydney Peppermint), Eucalyptus pilularis (Blackbutt), Eucalyptus botryoides (Bangalay), Eucalyptus robusta (Swamp Mahogany) and Angophora costata (Smooth-barked Apple).
According to Benson and Howell (1990) the alluvial flats at the head of bays such as Rushcutters Bay and Double Bay would have been forested with trees of Eucalyptus tereticornis (Forest Red Gum), Eucalyptus robusta (Swamp Mahogany), Eucalyptus botryoides (Bangalay) and small rainforest type pockets of Livistona australis (Cabbage Tree Palm). This was probably the only vegetation approaching rainforest in the Eastern Suburbs.
Remnant vegetation of this type can be found at Cooper Park, Parsley Bay and Vaucluse Bay.
Heath vegetation and low scrub (approximately two to five metres high) on the exposed rocky outcrops and shelves consisted of species such as Acacia longifolia (Sydney Coast Wattle), Allocasuarina distyla (Scrub She-oak), Kunzea ambigua (Tick Bush), Banksia ericifolia (Heath Banksia), Westringia fruticosa (Coast Rosemary), Eucalyptus obtrusiflora (Port Jackson Mallee), and smaller wildflowers and ground covers. Remnant vegetation of this type is found growing at Gap Park and Gap Bluff park at South Head.
Low forest and scrubland of mixed species to an optimum height of 14 metres. Angophora costata (Smooth-barked Apple), Eucalyptus botryoides (Bangalay), Banksia serrata (Old Man Banksia), Banksia integrifolia (Coast Banksia), Ficus rubiginosa (Port Jackson Fig), Allocasuarina littoralis (Black She-oak), Casuarina glauca (Swamp Oak) Kunzea ambigua (Tick Bush) and many smaller plant species. Remnant vegetation of this type exists at Nieslen Park and along the Hermitage Foreshore reserve and the 'Cresent area' of Parsley Bay Reserve.