At the bottom of the Garden there is an area, sheltered from cold winds, where a peculiar microclimate makes it suitable to host plants that in other situations could not tolerate the rigors of winter. Here there is an artificial pond, fed by waters that flow by fall into the system of ancient travertine channels. Around a pond some plants of the Australian sub-tropical zone find favorable conditions to grow, mainly from Tasmania (Eucalyptus L’Hér., Acacia L., Callistemon R. Br., ecc.), with plants of the southern hemisphere, as specimens of Cordyline australis (G. Forst.) Hook.