Book  (2018)  Page(s) 50-51.  
 
Parentage Tree of the variety 'Westerland' (Kordes, 1969)
Cläre Grammerstorf (Kordes 1957) = Harmonie (Kordes 1954) x Unnamed

Harmonie = Obergärtner Wiebicke (Kordes 1950) x Sunmist (Kordes 1940)
Unnamed = Golden Glow (Brownell 1937) x Obergärtner Wiebicke (Kordes 1950)

Website/Catalog  (2000)  Page(s) 60.  
 
H. Can, Cläre Grammerstorf, Kordes R., 1957

Book  (Apr 1993)  Page(s) 98.  
 
Cläre Grammerstorf Floribunda, deep yellow, 1957, 'Harmonie' x R. eglanteria seedling; Kordes. Description.

Book  (1985)  Page(s) 103.  
 
[Wilhelm Kordes] ...mixed his Sweet Briar hybrids with 'Peace' to obtain the yellow line, culminating after some generations in 'Cläre Grammerstorf' in 1957. Cläre is a rough looking character, coarse in leaf and growth, existing in gardens not so much in her own person, as in her yellow descendants, of which some are Reimer Kordes' 'Honeymoon', 1959; Niels Poulsen's 'Chinatown', 1963; and Sam McGredy's 'Arthur Bell', 1965.

Book  (1981)  Page(s) 324.  
 
Cläre Grammerstorf. F. (Kordes, 1957). 'Harmonie' x rubiginosa-seedling. Light yellow, large, double, open, petals retained; growth strong, bushy, upright, 0.7 m./2.3 ft.; foliage light green, glossy.

Book  (1978)  Page(s) 127.  
 
'Clare Grammerstorf' deserves particular attention, as leading Sweet Briar blood into yellow roses.  Kordes had  been  breeding with Sweet Briars, especially 'Magnifica', as a source of hardiness, because the market for  his roses was in Scandinavia as well as in Germany. He crossed a Sweet Briar hybrid with 'Peace', and introduced a rose called 'Kordes' Harmonie' from that cross in 1954. He then used `Kordes' Harmonie' as seed parent to a Sweet Briar hybrid, whether the same one we do not know, and the result was 'Clare Grammerstorf . It is a coarse rose, with huge leathery leaves of a somewhat unpleasant light green, and bright yellow flowers. We may regard it as a stud rose for the future, for although its decorative value was such as to preclude people from buying it, in the hands of breeders it is transforming modern  roses, particularly through its tough foliage, which resists disease, as well as in hardiness and vigour. The rather light leaves ..... are typical of the 'Clare Grammerstorf line.

Book  (1967)  Page(s) 48.  
 
Translated from Czech:
Cläre Grammerstorf - F.
W. Kordes 1957 - 'Harmonie' x seedling of R. eglanteria.
Upright shrub, lush growth, 70-80 cm tall. Foliage is large, light green, glossy. Ovoid buds, 2-7 per stalk. Flower bright light yellow. In less favourable conditions more susceptible for disease.  
Suitability for use: For height and colouring in intermediate part of landscaping.
 

Book  (1958)  Page(s) 60.  
 
Cläre Grammerstorf. F. (Kordes, '57.) Harmonie X R. eglanteria seedling. Bud ovoid; fl. very large, dbl., high centered, yellow. Fol. leathery, glossy. Very vig., bushy; profuse bloom.