120 gardens in Alsace, the Pays de Bade and Basel are open to the public.  You can find the program with all the details on the internet.

Another interesting place to visit is the Forêt Magique in Ribeauvillé created and kept by Lucien who welcomes you by appointment throughout the year.  The trunks and branches are sculpted, trimmed, and transformed into living pieces of art (trees are very adaptable).  Call 0389736507 to make your appointment.  Take the train from Colmar to Ribeauvillé.  46, Rue de Landau across from the camping site.