La Mortella (Italian: place of myrtles) is a private garden in the island of Ischia, Italy. It was first opened to the public in 1992. It was created by Susana Walton (1926–2010), wife of the composer William Walton, in 1950 as the main residence for the couple.
The garden, located in Forio-San Francesco, was originally the property of the English composer William Walton. Walton lived in the villa next to the gardens with his Argentine wife Susana née Gil. When the composer arrived on the island in 1946, he immediately called Russell Page from England to lay out the garden. Tropical and Mediterranean plants were planted and some have now reached considerable proportions. The gardens include views over the city and harbour of Forio.
A museum dedicated to the life and work of William Walton is now part of the garden complex. It hosts the William Walton Foundation and a Greek Theatre where Italian and foreign schools of music perform more than 70 weekend concerts, plus masterclasses and a programme for composers from Harvard University. In 2004 it was awarded First Prize as il più bel parco d’Italia (the most beautiful park in Italy) by the American company Briggs & Stratton, against competition from 100 other gardens.