The earliest beginnings of the gardens go back to 1779, when the Accademia dei Regi Studi created the chair of "Botany and medicinal properties".

A modest plot of land was allocated to develop a small botanical garden dedicated to the cultivation of plants with medicinal benefits, for the twin objectives of general learning and improving public health.

These bastions were demolished in 1774–1778 under the praetorship of Antonino La Grua Talamanca, marchese de Regalmici, and later Prince of Carini, and reassigned for the botanical gardens.

This initial garden allotment soon proved too small, and in 1786 it was decided to move to the present site, right next to the Piano di Sant'Erasmo, best remembered for the unfortunate events that occurred there during the Spanish Inquisition.

Patronizing the development was the praetor Bernardo Filangieri, count of San Marco and the noblemen Giovanni Battista Paterno Asmondo and Ignazio Vanni.

To this day they are called the Calidarium and the Tepidarium because originally they housed plants from warm and temperate zones respectively (caldo meaning "hot" in Italian).

Also known as the nuovo settore (the new zone), it comprises the southern section of the gardens within which the plants are arranged in accordance with the classification system of Engler.

The non Sicilian specimens are mainly from Portugal, Spain, France, Corsica, Sardinia, Greece, Crete, Cyprus, Algeria and Egypt.

The main objective of the bank is the conservation ex situ, both short and long term, of all seeds endemic to the region, rare or endangered.

The bank forms part of the RIBES network (Rete Italiana delle Banche per la conservazione Ex-Situ del germoplasma).

In this context, the relationship between the Berlin Botanic Garden, under the stewardship of Adolf Engler, and those of the originating areas of the new world proved to be extremely important.

As an illustrative example of the role of the Palermo Botanic Garden, consider the introduction into the Mediterranean of the mandarin (Citrus deliciosa) and the loquat (Eriobotrya japonica).

Various species of bamboo grow nearby and directly behind here, atop a small artificial hill, there is a healthy specimen of the drago tree (Dracaena draco).

Not too far away one can see the tallest plant of the gardens, a magnificent Araucaria columnaris, and the largest overall in terms of volume, a gigantic specimen of Ficus macrophylla, with its typical aerial roots, imported from Norfolk Island (a territory of Australia in the Pacific Ocean), in 1845.

The giardino a succulente (the garden of succulents) of the bioecological zone is home to numerous species of the genus Aloe and various other plants of arid regions, including Cereus, Crassula, Euphorbia and Opuntia.

In the following stage of the gardens' development Zamiaceae Ceratozamia mexicana and Dioon edule, were both introduced from Mexico, as was Cycas circinalis, an elegant species from the Indian sub-continent.

Lastly we have the medicinal plantings, including Artemisia absinthium, Datura stramonium, ginseng (Withania somnifera), la camphour (Cinnamomum camphora) and the opium poppy (Papaver somniferum).