As this is a parasitic species, all flower visits will be for nectar only.
Westrich (1989) lists the following as nectar sources: Taraxacum officinale, Cirsium, Carduus, Onopordum, Centaurea (Asteraceae) Kanutia arvensis and Scabiosa (Dipsacaceae).
Celary (1989) lists the following nectar sources in Poland: Primula elatior (Primulaceae); Thymus sp. (Lamiaceae); Petasites officinalis, Cirsium sp., Centaurea sp., Taraxacum officinale (Asteraceae).
In Spain, Ornosa & Ortiz-Sánchez (2004) list the following plant families as providing nectar: Rosaceae and Asteraceae.