The Royal Botanical Gardens, commonly known as 'Peradeniya Gardens' is probably the most popular garden in the country. It covers 147 acres and is said to attract close to 2 million visitors every year. It is a glorious expanse of well-kept trees, flowers and pathways, some of which are centuries old. While officially established under the British colonial government in 1843, the origins of the Botanic Gardens date as far back as 1371 when King Wickramabahu III ascended the throne and kept court at Peradeniya near the Mahaweli river. This was followed by King Kirti Sri and King Rajadhi Rajasinghe. A temple was built on this location by King Wimala Dharma, but it was destroyed by the British when they were given control over the Kingdom of Kandy.
Thereafter, the groundwork for a botanical garden was formed by Alexandar Moon in 1821. He used the garden for coffee and cinnamon plants. The Botanical Garden at Peradeniya was formally established in 1843 with plants brought from Kew Garden, Slave Island, Colombo, and the Kalutara Garden in Kalutara. The Royal Botanic Garden, Peradeniya was made more independent and expanded under George Gardner as superintendent in 1844. On Gardner's death in 1849 George Henry Kendrick Thwaites became superintendent. He served until he resigned in 1879, when he was succeeded by Henry Trimen, who served until 1895. The garden came under the administration of the Department of Agriculture when it was established in 1912.
There are avenues in the River Drive such as Cook's Pine Avenue, Palmyra Palm Avenue, Double Coconut Avenue, Cabbage Avenue, and Royal Palm Avenue. The classical Avenue of Palms is in this Garden. One item with a significant history is the Cannonball Tree planted by King George V of the United Kingdom and Queen Mary in 1901. It is often laden with fruit, which are thought to resemble cannonballs.
During World War II, the Botanic Garden was used by Lord Louis Mountbatten, the supreme commander of the allied forces in the South Asia, as the headquarters of the South East Asia Command. Not only the historical importance of this garden, but also there are various biodiversity importance of this site. The vegetation is purely tropical, being characterized by an abundance of climbing plants or lianas, palms, bamboos, pandanus or screw-pines, epiphytes (orchids, ferns etc.), and lofty trees, the latter often having buttresses roots. The leaves are generally large, thick and leathery; the flowers usually brilliant and considerable in size, and the fruits often of immense proportions and borne on the trunks of trees or older branches.
A signboard at the entrance, with a map, feature a numbered circuit from 1-30. The corresponding numbers are placed at strategic points on the route, black on a yellow background. 60 ha (150 acres) gardens, where you can easily stroll around a whole day, are stuffed with a bewildering variety of local & foreign tree & plant species. There are around ten thousand plants & trees inclusive of 4000 labeled species. One of the most interesting sites here is bizarre-looking snake creeper, whose tangled aerial roots look just like a writhing knot of vipers.
You can also visit the great circle which is a grassy central area of nearly 4 acres in extent. Around the circle is a diverse array of trees planted by dignitaries, who had visited the Peradeniya Royal Botanical Gardens.
A "Flamboyante" of Madagascar (Poinciana regia), planted by Princess Henry of Prussia in 1899; a "Bo" (Peepal) tree (Fiscus religiosa), planted in 1875 by King Edward VII; a "Na" tree, or Ceylon Ironweed (Mesua ferrea), planted in 1891 by Czar of Russia; Brownea grandiceps tree planted by the King of Greece in 1891; Amherstia nobilis, planted by Prince Henry of Prussia in 1898;‘Asoka" tree (Saraca indica) planted by Emperor of Austria in 1893; "Cannonball" tree (Couroupita guianensis), planted by the Prince of Wales in 1901.