To recall the historical roots of the Botanical Gardens, in 1998 a collection of plants of phototherapeutic interest was realized. Covering a trapezoidal area of 541 m2, a total of 154 species coming from natural environments, private and public collections are cultivated.

The plants are located in plots of 1 m2 arranged to form two parallel rows, separated by a central walkway. Each plant is provided with an identification tag, bearing information even on the main therapeutic properties, the parts of the plant from which the active components are extracted, and the distribution of the species in Italy.

For each plant has been recreated a suitable environment for growth, in some cases it was sufficient to place the specimen in shade or sun, in other cases the characteristics of the soil have been changed through specific fertilizers. Specialized staff takes constant care of the individual parcels, as each species has different crop requirements (irrigation, fertilization, pruning, etc.); weeding of the area is manually done, in order to identify the species of interest from the state of seedlings and remove only selected weeds. Particular attention is given to the collection of seeds; these are filed and stored in order to reproduce them for any future replacement, both here and at the Germplasm Bank (ex situ conservation) in cases when the species is of particular interest.

Some species are common to the general public, such as onion (Allium cepa L.), garlic (Allium sativum L.), aloe (Aloe vera (L.) Burm), and wormwood (Artemisia absinthium L.); while others are less known, such as the Californian poppy (Eschscholzia californiana Cham.),the licorice (Glycyrrhiza echinata L.) or the grindelia (Grindelia hirsutula Hook. & Arn.).