The grounds of Hambledon have been converted into a public reserve. They still contain some of the original or early layout (drive alignments, paths) and plantings put in by John Macarthur when it was part of the Elizabeth Farm Estate. These include several mature (some now in decline) English oak trees (Quercus robur) in the garden believed to have been planted by John Macarthur. Other mature trees gracing the grounds from early decades in Hambledon's existence include a cork oak (Quercus suber), jacaranda (Jacaranda mimosifolia), Illawarra plum/ plum or brown pine (Podocarpus elatus), firewheel tree (Stenocarpus sinuatus) and Osage orange (Maclura pomifera), a tree now rare east of the Great Dividing Range. Some of these plantings can be dated from shipping lists Macarthur brought with him of plants on board the Lord Eldon in 1817.