The Botanical Gardens of St. Vincent are the oldest in the Western Hemisphere and a guided tour by one of the official tour guides around the 20 or so acres of land is worth every penny because without the knowledge of a guide you will miss 80% of what is on offer.
I have spend numerous times strolling around these cool, relaxing and very well established gardens marvelling at the knowledge of the guides. Allow 2 hours or so and enjoy the experience of seeing the breadfruit tree grown from the original brought by Captain Bligh (of Mutiny on the Bounty infamy) in 1793, the Soufriere Tree (the national plant of St. Vincent & the Grenadines), and see the extremely rare 'Vincy Parrot', native only to the island.