Book  (2021)  Page(s) 200-202.  Includes photo(s).
 
Damask roses .... 'Helga Schiemann' ... Description ....According to the DNA studies 'Helga Schiemann's nearest relatives are ..'Kazanlik' and the genetically identical 'Quatre Saisons' and 'Quatre Saisons Blanc Mousseux', wirh a similarity index of 64,0%. Thenext nearest sorts are 'Geschwinds Nordlandrose' and 'Belle Cathérine with its sports 'Parten' and 'Svea', all in the Damask group. Their similarity indices with 'Helga Schiemann' is 56,0 respectively 54,2%. Morphologically 'Helga Schiemann' reminds of 'Geschwinds Nordlandrose'. The number of petals is the best characteristic to differentiate the two varieties.