The park has several very large London Plane trees. An independent analysis by some members of the park community found that the London Planes near the duck pond have an average girth of 6.55 metres, which a specialist confirmed equals over 400 years of age, meaning that they were likely planted at a time when royalty were staying at Theobalds Palace, which stood on the grounds. John Tradescant was Head Gardener at Hatfield House before the Cecil family moved to Theobalds - it is believed that it was in Tradescant's garden in Vauxhall that the hybrid tree which would become known as the London Plane was created.
Two Amur Cork Trees were donated to Waltham Cross and planted in Cedars Park by Waltham, Massachusetts, USA in the 1930s and in August 1980. These both died and a new one was planted in recent years, which was unfortunately ring-barked (likely by muntjacs) in 2019 and died in 2020, despite attempts to repair it using mud plaster.
To mark the 50th anniversary of the creation of the United Nations, the Cheshunt Royal Naval Association planted rose bushes and an oak tree in Cedars Park. This was followed up in 1996 with several trees being planted in the northwestern area of the park now known as Zone A. The oak was planted in partnership with Broxbourne Council, who presented the Cheshunt RNA with a certificate acknowledging that the tree is the 2000th planted by the council since 1987. On 22/4/2004, the Cheshunt RNA planted a tree near the entrance, to commemorate the 60th Anniversary of the Battle of the Atlantic.