State boundaries limit human contacts in a homogenous context of a landscape and its natural features, including plants. After nine centuries of separation, finally the two territories in Slovenia share the same political history. In this paper we tried to answer the question to which extent the past political borders, geographical and cultural drivers affect today's traditional knowledge on wild plants use of Slovenians, living unified in the same political entity. Data were collected using 60 in-depth semi-structured interviews, from March to August 2019, in two municipalities: Komen at Karst and Izola in Istria concerning food, medicinal, economic use, and local customs. The results indicate a quite large divergence in ethnobotanical and ecological knowledge between the two studied areas. In the Komen area, many people still use wild plants daily for various purposes (Taraxacum officinale, Melissa officinalis, Urtica dioica, Cornus mas, and Sambucus nigra). In contrast, this is limited to fewer people in the Izola area and mainly to seasonal use of specific plants (Asparagus acutifolius, Rosa canina, Salvia officinalis, Foeniculum vulgare and Rubus caesius). Unusual for the Mediterranean is the use of young shoots of Clematis vitalba, in the Izola area prepared as omelettes. We can assume that these differences are partly due to minor differences in climatic conditions and partly due to the influence of different cultures and cuisines. In the first place, the impact of Austro-Hungarian eating habits and cuisine can be seen on the area around Komen. Moreover, temporal "layers of knowledge" across the time scale are additionally mixed by the immigration of people from other parts of Slovenia or abroad, or with the influence of local herbal specialists. At last, we conclude Komen area knowledge is alive and homogeneous, and more connected to their local identity.
Keywords: North Adriatic Karst; cultural value; historical heritage; interviews; local knowledge; traditional uses.