Verbascum halacsyanum is a very local angiosperm, endemic to the hilly area flanking the city of Kavala in Northern Greece. The area of occupancy (AOO) and extent of occurrence (EOO) of this species are both 12 km². The species is known from three ruderal sites corresponding to two locations, whereas the habitat is subjected to ongoing decline due to anthropogenic activities. Under criteria B1ab(iii)+2ab(iii), the species qualifies for listing as Endangered. However, the population size observed in the summer of 2023 was less than 50 mature individuals fulfilling the Criterion D for Critically Endangered. It is thus listed as Critically Endangered.

Verbascum halacsyanum is a Greek steno-endemic species distributed in a small hilly area in the vicinity of the seaport city of Kavala, Northern Greece. (Murbeck 1933, Dimopoulos et al. 2013). There are only two historic records (without exact coordinates), whereas the species is currently known from three sites.

Verbascum halacsyanum is known from three small or very small subpopulations. The first two are located above the city of Kavala. The larger one, consisting of 30 mature individuals, was found in an abandoned almond field, flanking dirt road sides and a land plot with a view to the sea, visited by hikers. The second subpopulation, consisting of only two mature plants, was found on granite rocks on a cut slope of the perimeter road. The third subpopulation, consisting of less than 10 mature plants, is located ca 7 km south west of the Kavala on a disturbed site and flanking granite rocks by the motorway.

Verbascum halacsyanum is a biennial angiosperm which inhabits rocky granite slopes and disturbed places including abandoned fields and roadsides. The surrounding vegetation flanking the subpopulations of the species is characterised by a Quercus coccifera shrubland accompanied by phrygana such as Cistus creticus. The species flowers from May to June.

The larger subpopulation of the species, i.e. in the almond field and surrounding area, is subjected to: i) the will of the owner of the almond field if there is still an owner, and ii) municipal maintenance activities which include the pruning of the remnant Quercus coccifera shrubs and possibly periodic cleaning of herbs like Verbascum halacsyanum from the site. Trampling by hikers and garbage was also observed on the site which further contributes to the decline of the habitat. Municipal maintenance activities as a threat to this species also apply to the subpopulation south west of Kavala. The developing inflorescences of several Verbascum spp. may be consumed by livestock, however, no grazing was indicated in the reported sites in 2023 and thus the extent of this threat is unknown for the particular species.

This species is not utilised or traded.

Verbascum halacsyanum is protected at national level under the Greek Presidential Decree 67/1981 for the protection of native flora and wild fauna. However, no conservation measures are implemented for this angiosperm, whereas the municipal authorities and people of the city of Kavala are, in all probability, unaware of this very rare and threatened plant. The hilly area above the city should ideally be designated a reserve for V. halacsyanum with several conservation actions implemented including the almond field being fenced off, researching the whole area for additional subpopulations of plants and monitoring the existing subpopulations. Raising awareness of this very local species to the municipal authorities and people of Kavala could be proved beneficial for its future existence. Additionally, ex situ conservation strategies of cultivating the species in botanical gardens and of depositing seeds in seedbanks should be undoubtedly considered.