In Llanarthne in rural Wales it has taken three years to turn the old, neglected estate of Middleton Hall to the National Botanic Garden of Wales, the first to be built in the UK for over 200 years. With its innovative architecture and an agenda of research, conservation and education, it aims to provide the model for a 21st-century botanical garden. Kerry Ten Kate investigates. Producer Gwenan Thomas

Choice: The National Botanic Garden of Wales has just opened in Carmarthenshire (above). Kerry Ten Kate introduces The Plant Hunters (11.00am R4 FM) who have been travelling the world looking for plants to stock it. These include Dr Wolfgang Bopp, part of whose job is to simulate bush fires with a blow-torch, in order to facilitate the regrowth of trees from south west Australia. A scary new series begins tonight. It Couldn't Happen Here (9.00pm R4) we think, when reading of the effect of West Nile fever on New York last summer. But, actually, it could. Sue Armstrong counsels eternal vigilance: in the global village, we're only a bad plane-trip from disaster. More cheerfully, it's nearly the Queen Mother's 100th birthday. Centenary tributes start now in A Service of Celebration and Thanksgiving (11.30am R4 FM) from St Paul's Cathedral. SG