The University of Costa Rica runs the exceptional 11-hectare Lankester Gardens, started as a private garden by British orchid enthusiast Charles Lankester in 1917, then turned over to the university for public administration in 1973. Orchids are the big draw here: there are more than 1000 varieties, at their showiest in April. The garden is wheelchair accessible. Find it about 5km west of Paraíso on the road to Cartago.
There's also a Japanese garden, as well as areas full of bromeliads, palms, heliconias and other tropical plants. Guided tours around the garden in English and Spanish are available by prior arrangement.