Verbascum delphicum is endemic to Greece, where it is known from three, well-separated mountainous areas and is reported from fewer than 10 sites in total. Its distribution is fragmented, however it is not known whether the population is severely fragmented (under the IUCN definition of this term). Its area of occupancy (AOO) and extent of occurrence (EOO) are both small (AOO = 32 km² and EOO = 2,069 km² respectively) and the sole subpopulation on Mt Parnitha on the mainland (Attica) is severely threatened by fire-induced habitat degradation and overgrazing by Red Deer (Cervus elaphus). On the island of Euboea, grazing by livestock constitutes a threat of unknown severity. There is no indication of an increase in size of subpopulations in Euboea to potentially offset the trend of reduction observed in the mainland subpopulation. On account of i) its restricted AOO and EOO, and ii) ongoing reduction in the quality of the habitat and in the number of mature individuals in Attica, but with unknown severe fragmentation or number of locations, the species is assessed as Near Threatened (nearly meets criterion B). It should be noted that on the mainland the subspecies Verbascum delphicum cervi is considered to be Critically Endangered (CR). More research is needed to confirm the status of the subpopulations on Euboea and to clarify threats there to be able to estimate the number of locations this species occurs in: this may result in the species being reassessed in a higher threat category.

Verbascum delphicum is a Greek endemic species known from the island of Euboea and from Attica, Central Greece (Dimopoulos et al. 2013). In Euboea, the species is reported from a few sites on two mountain areas, i) the Dirfi/Xsirovouni area in the central part of the island and ii) Mt Ochi in the southeasternmost part (Strid 2016a,b; Strid 2022). On the mainland, the species is represented by subspecies cervi which is a very rare local endemic of Mt Parnitha (Zografidis 2016).

The population size of this angiosperm is unknown in Euboea, but the assessor has never observed large subpopulations. On Mt Parnitha on the mainland, the species is very rare with no more than 50 mature individuals counted in 2016 and with a 20% reduction of the population size reported over the three years 2013–2016 (Zografidis 2016).

Verbascum delphicum is a short-lived perennial or biennial species of the forest zone. On the mountainous region of central Euboea (Mts Dirfi and Xirovouni) and on Mt Parnitha, Verbascum delphicum inhabits Greek-fir or mixed Abies-Castanea woodlands (Strid and Tan 1991; Strid 2016a,b). On Mt Ochi (were Abies is absent), the species is reported from Castanea woodlands or from sub-montane to montane, open shrublands, dominated by thick patches of Pteridium aquilinum (Zografidis 2016).

There is limited information regarding threats to Verbascum delphicum on the island of Euboea. The developing inflorescences of the plants can be consumed by livestock, however the extent and severity of this threat is not known. On the mainland, the subspecies V. d. cervi is threatened by fire-induced habitat degradation and by overgrazing. In particular, the disastrous fire of 2007 destroyed more than 3,100 ha of Greek fir forest including suitable habitat for V. d. cervi (Zografidis 2016). The subspecies is forced to adapt in a more open ecosystem, where regeneration of the forest is very slow. Overgrazing by Red Deer (Cervus elaphus), which overpopulate the Mt Parnitha National Park, is an additional significant pressure (Zografidis 2016).

This species is not utilised or traded.

Verbascum delphicum is protected at national level under the Greek Presidential Decree 67/1981 for the protection of native flora and wild fauna. The records of this species from Mts Ochi and Parnitha fall in the Natura 2000 protection network (GR2420001, GR3000001). No specific conservation actions are implemented. Raising awareness of the endemic plants of Greece, including V. delphicum, is advisable. However, for the Critically Endangered subsp. cervi on the mainland, immediate conservation measures in the National Park of Parnitha should be implemented. More research is needed to confirm the status of the subpopulations on Euboea and to identify any threats currently affecting the species there.