Yverdon-les-Bains, Vaud
Elevation: 435m (1,427 ft)
Two fruiting plants by the edge of a pond in the Japanese Garden across the road in front of the main railway station.

Information and photos in November 2015, from Swiss resident Sylvain Gailloud who tells me that the area is due for re-development in the next few years. See details of the project here.
There are two specimens in the gardens.
This is the better one, in the small lake-side area reached by a passage under the road from the main garden. Multi-stemmed and plenty of fruit in November 2005.
Geneva Botanic Garden
....in Switzerland

Zurich Botanic Garden
There is a lovely group of Poncirus trifoliata plants either side of the path through the south-facing, dry rock garden.
All carried fruit when photographed in  August 2005.
page created 16Nov2015

Click here  for location details of these and other Poncirus trifoliata plants.