The Istana will host guided nature walks of its expansive grounds during open houses starting from Saturday.

Led by volunteer guides with the National Parks Board, members of the public will get to tour areas such as the Spice Terrace and Queen Victoria Garden while learning facts about the flora and fauna there. For example, the Istana has two resident Oriental Pied Hornbills, other birds such as the Lesser Whistling Duck and the Oriental Magpie Robin, and a Tembusu tree more than 150 years old.

Visitors will also get to hear intimate anecdotes about some of the species. The Bread Flower climber found within the grounds, for instance, was a favourite of former prime minister Lee Kuan Yew and his late wife because of its sweet fragrance.

On Tuesday, President Tony Tan Keng Yam hosted about 30 students and visitors on a special preview of the guided tour. The tours on Saturday's Chinese New Year open house will be held at half-hour intervals between 10am and 4pm. They are priced at $4 for Singapore citizens and permanent residents and $10 for other visitors. All proceeds will be donated to the Community Chest.

The Istana was built on the grounds of a former nutmeg plantation in 1867. Its grounds are home to about 10,000 trees.