Leoncina Reserve was formed on the 8.67 ha in 2001. It lies in the municipality of Krasiczyn in Przemyśl Foothills. It was set up to host a cluster of European bladdernut.
Leoncina Reserve is one of the few communities of European bladdernut (Staphylea pinnata) in its natural range. European bladdernut covers the southern and south-western Europe, Asia Minor and the Caucasus.