I visited these gardens back in 2002, and they are definitely worth seeing, and I'd also suggest you give yourself some extra time and see the higher elevation annex garden in Hakgala, which is high enough in altitude to be able to grow more temperate/Mediterranean climate plants from California and South Africa. It was at Hakgala that I first fell in love with the golden haired over silver foliage Strobilanthes gossypinus shrub, surrounded by Agapanthus and Monterey Pines in one of the municipal parks in Hakgala. The nearby town of Kandy makes a very convenient base for seeing both gardens. A very good collection of palms, and of course the Amherstia tree flowers very well at this elevation and latitude.

I visited the garden about 10 years ago and it is well worth the trek. There is a particularly good orchid collection, including an enormous Grammatophyllum scriptum growing in a bed of stones in full sun. I hope it is still there.