During the days of the Kandyan kingdom, Udawattakele was known as "Uda Wasala Watta" in Sinhalese meaning "the garden above the royal palace".

[1][2][3] The Sri Lanka Forest Department has two offices in the reserve, one of which (at the southeastern entrance) has a nature education centre with a display of pictures, posters, stuffed animals, etc.

The legend says the brahmin brought a sapling of Jaya Sri Maha Bodhi here and planted it in the present site of Natha Devala.

[14] On two hilltops in the southeastern side of the forest the overgrown remains of a garrison post from the first British occupation of the Kandyan Kingdom [15] can be found.

On 24 June 1803 the forces of King Sri Wickrama Rajasingha attacked this post where the British troops were stationed in Kandy and made the garrison (mostly consisting of Malay and 'Gun Lascar' or Sepoy mercenaries) prisoners.

[12] During rainy weather there are leeches lurking along paths that will attempt to suck blood from the feet and legs of unwary visitors.

A great variety of plant species are found in the relatively unspoilt northern and eastern sides of the forest.

Some common indigenous tree and shrub species are Acronychia pedunculata (Sinhalese: "ankenda"), Artocarpus nobilis ("wal del"), Artocarpus heterophyllus ("kos"), Caryota urens ("kitul"), Aglaia elaeagnoidea ("puwanga"), Bombax ceiba ("katu imbul"), Canarium zeylanicum, Cinnamomum verum ("kurundu", cinnamon), Ficus virens, Filicium decipiens ("pihimbiya"), Aphananthe cuspidata ("wal-munamal"), Goniothalamus gardneri, Haldina cordifolia, Hunteria zeylanica, Mallotus tetracoccus, Mesua ferrea ("na", iron-wood), Michelia champaca ("sapu"), Mangifera zeylanica ("atamba"), Neoclitsea cassia ("dawul kurundu”, wild cinnamon), Glycosmis pentaphylla (orangeberry, doda-pana), Litsea quinqueflora, Micromelum minitum ("wal karapuncha"), Pavetta blanda, Psychotria nigra, Vitex pinnata ("milla") and Walsura gardneri.

Some other species are Anamirta cocculus ("Tittawel”), Diploclisia glaucescens, Hiptage bengalensis, Hypserpa nitida ("Niriwel"), Morinda umbellata ("Kiri-wel"), and Paramignya monophylla.

[25] Orchid species, mostly epiphytic, include Cymbidium bicolor, Luisa teretifolia, Polystachya concreta, Thrixspermum pulchellum, Tropidia curculigoides and Vanda testacea.

[26] The sanctuary is home to many species of non-flowering plants, pteridophytes, such as the many kinds of ferns growing on steep banks along the shady road on the eastern side of the hill ridge.

[28] About half of the forest, mostly on the southwestern side, is heavily invaded by exotic tree and creeper species.

[20] The endemic bird species are Layard's parakeet, yellow-fronted barbet, brown-capped babbler and Sri Lanka hanging parrot .

Common hill myna, golden-fronted leafbird, blue-winged leafbird, spotted dove, emerald dove, Tickell's blue flycatcher, white-rumped shama, crimson-fronted barbet, brown-headed barbet crested serpent eagle, and brown fish owl are regularly seen and heard in the forest.

[35] Other invertebrate include giant forest scorpions Heterometrus spp., spiders such as the poisonous Sri Lankan ornamental tarantula (Poecilotheria fasciata), fireflies, beetles, jewel bugs, bees and wasps.

The invasive tree and creeper species have no natural enemies such as diseases or insects and animals that feed on them and therefore grow and multiply much more rapidly than in their native habitats.

About half of the forest is already heavily or completely invaded and smothered by exotic, invasive trees and creepers.

Necessary control measures would be the uprooting of seedlings, collecting and destroying seeds, and removal of mother trees and creepers.