Book  (Jan 1999)  Page(s) 212, 213.  Includes photo(s).
 
Page 212: [Photo]
Page 213: Duchess of Marlborough Tree Peony. Kelway UK [no date given]. Semi-double Pink... silky ruffled petals in warm tones of flesh pink around a tidy boss of short stamens...

Magazine  (1899)  Page(s) 364.  
 
....Duchess of Marlborough, blush, with deeper centre; Mrs. William Kelway, large White; Lady Skelmersdale, delicate blush; Lord Kitchener, shining maroon....

Magazine  (18 Jun 1898)  Page(s) 662.  
 
Plants Recently Certificated.
Pæony Duchess of Marlborough.—Another Tree Pæony with very large, but in this case semi-double, flowers, which are not so flat as those of other forms. The colour is a bright satiny rose, the notched petals having, moreover, a silvery margin. Messrs. Kelway & Son.

Website/Catalog  (1897)  Page(s) 127.  
 
KELWAY'S NEW TREE PÆONIES for 1897.
Magnificent Introductions.
The fact that bald statements as to the colour and size of flowers gives no true idea of their actual living beauty is well known.  It is particularly true when such plants as these new varieties of Tree Pæonies are in question.  They certainly beggar description.
Duchess of Marlborough, semi-double, pure flesh-pink.  21/-