They come from Central Asia and were introduced together with the alba variety, in the mid-eighteenth century, when the Bourbon monarchs tried to stimulate the economy. Trees planted in the Alcázar were leased to individuals who were responsible for collecting leaves to then sell them to breeders of silkworms. Mulberry trees of the gardens of the Alcazar at that time would come to exceed three hundred specimens.
Unlike the white mulberry, black berries of morality are without stalks, thick and very acidic before maturity, to be sweet afterwards. The blackberry is edible and contains a 10% of sugar and some vitamins. The syrup obtained with its fruit is used to combat soar throat.
In the time of Charles V, the Italian Andrea Alciato wrote some poems as moral lectures, called emblems. The examples used to build these precepts are based on two main sources of inspiration of the cultural moment in which the author writes, the Renaissance: Mythology and classical antiquity on one side and the Nature on the other. Thus, he has a series of emblems inspired in trees. Among them is the mulberry interpreted as an allegory of prudence because it does not flourish until the summer: more sensible, the mulberry does not turn green until the cold has passed. Texts like the one of Alciato open the door to possible symbolic interpretations of the Alcazar Gardens during Renaissance.