Cherry Helen
TerminatedVerbascum L. · Mullein
Dick Degenhardt
Variety traits
Frost Hardiness of Mullein
Verbascum L.
The frost hardiness of mullein is determined by the classification of species within USDA hardiness zones 5–8 and their ability to withstand temperatures down to -26 °C, which critically affects the plant's life cycle and flowering process.
In the reference 3 varieties crop Mullein, where this is mentioned in the description.
For members of the genus Verbascum L., frost hardiness is primarily assessed by their ability to overwinter in open ground, corresponding to USDA zones 5–8. Certain species, such as Verbascum thapsus, demonstrate resistance to sub-zero temperatures down to -20 °C and -26 °C, as confirmed by successful cultivation in the corresponding climatic regions.
Frost hardiness directly determines the plant's life form, which is why perennial and biennial species in cold climate regions are often cultivated as annuals. A physiologically significant factor for biennial forms is the winter cooling of basal leaf rosettes in the first year of life, which serves as a necessary stimulus for subsequent flowering.
General information about the subject — on the page Frost hardiness.
Varieties of Mullein mentioned in the description
Selection based on the description text, not on official evaluation: these data are absent from registers. For specific variety details, please refer to its profile.