Trsteno is most famous for its arboretum, the oldest in this part of the world.

The arboretum was erected by the local noble family Gučetić/Gozze in the late 15th century, who requested ship captains to bring back seeds and plants from their travels. The exact start date for the arboretum is unknown, but it was already in existence by 1492, when a 15 m span aqueduct to irrigate the arboretum was constructed; this aqueduct is still in use.

The arboretum passed into Yugoslav state ownership in 1945, and was declared a natural rarity in 1948. Since 1950 it has been managed by the Croatian Academy of Sciences and Arts. In 1962 the Arboretum Trsteno was registered in the list of protected natural monuments list as a monument of landscape architecture. The protected area covers around 255,000 square metres.

Trsteno suffered extensive damage and looting during the Yugoslav wars when on October 2nd and 3rd, 1991, the Yugoslav People's Army launched a series of gunboat and air attacks and set the Arboretum afire, destroying a large part of it, and causing partial damage to the summer residence and the oldest part of the arboretum. The arboretum was further severely damaged in 2000 by a forest fire during a drought, when around 120,000 square metres were lost in fire.

The pride of the arboretum, two Oriental Planes located on the central market place of Trsteno, survived both disasters undamaged. They are over 500 years old and are unique specimens of its kind in Europe. The ancient trees are both about 45/60 m tall and 5 m trunk diameter.

Within what was once the noble family's country house, there is the oldest Renaissance park in Croatia, designed in 1502, with numerous exotic plants.