Gunter, I think you may have posted to the wrong forum. This forum is about starting your own plants. You may want to review the many recommendations on the Garden Sources Forum, linked below. Also, since there are literally thousands of great nurseries, it might help to specify which plant you are looking for when asking for a source.

There are two more online resource that might also be of great help. They are PlantScout and Garden Watchdog. For very best results, they can be used in conjunction. They can be found at:

Garden Watchdog Link: http://davesgarden.com/products/gwd/

PlantScout Link: http://davesgarden.com/products/ps/

Here is a link that might be useful: Garden Sources Forum here on Gardenweb

Thank you!