Lokrum island covers an area of 2 hectares and is situated on the southeastern Adriatic Sea, near the Old town of Dubrovnik. In 1976, it was declared a natural forest reserve. Lokrum is mostly covered with thick vegetation. Many types of "true" Mediterranean vegetation (Eumediterranean) are found over a small area. According to research, there are around 400 species of vascular flora on the island. The climate is characterized by dry and hot summers, with mild, rainy winters. The annual average temperature is 16°C and precipitation is 1300 mm. There are 2,584 sunny hours per year.
In the public area today (1 ha), there are around 500 species, mostly trees and shrubs, and approximately 200 succulents in the greenhouse. Many introduced plant species, which are not on display to the public, grow on the former experimental fields, which are now under reconstruction, following many years of neglect. Besides research into plant acclimatization, the education of visitors and children, and being a tourist attraction, there is also a possibility of growing local plants that are threatened in the wild. This will help to protect them in their natural habitat. Today, the garden is a part of the Institute for Marine and Coastal Research, University of Dubrovnik. It has one botanist and one part-time gardener. Although the garden is forty years old, it is still far from its final appearance. In the public area of the botanical garden, plant species are grouped mainly according to the plant family, or, in some cases, according to the same conditions they require (for example: rockery). The map shows the location of the most represented plant families in the botanical garden. Probably the most attractive part of the garden is the one with the succulents. Cacti (fam. Cactaceae), puyas (fam. Bromeliaceae) and agaves (fam. Agavaceae) are planted here, mostly of American origin.