Grow Heirloom Tomatoes - Plant Principe Borghese Tomato Seeds. Famous Italian heirloom tomato is plum-shaped and borne in clusters. In dry areas, branches of these tomatoes can be hung up to dry until leathery! Very meaty with little juice and few seeds, Principe Borghese has a rich tomato taste that is wonderful in sauces as well. Determinate vines will need support.