This calendar shows when specific types of herbs are flowering (in the Netherlands), each herb is explained by a short video. Parietaria judaice and Ambrosia artemisiifolia are the most allergenic.
Most allergenic herbs:
Rumex acetosa
Plantago lanceolata
Parietaria judaica
Urtica dioica
Artemisia vulgaris
more information about Artemisia vulgaris >>
Chenopodium album
Ambrosia
more information about Ambrosia >>