Website/Catalog  (1938)  Page(s) [12].  
 
Japanese Peonies
This type is characterized by five or more cup-shaped, rounded guard petals, surrounding a large center of staminodes or petaloids.
Gertrude—An excellent variety. Very soft carmine-pink flowers. A heavy comb of clear yellow staminodes; incurved. Late....$1.75 Each

Book  (1907)  Page(s) 94.  
 
991. GERTRUDE; P.
(1) 1895, The Gardening World, Vol. 11, p. 668.
(2) 1899, Peter Barr's Cat.
(3) 1905, De Graaff Bros. Cat., p. 27.

Magazine  (7 Jul 1900)  Page(s) 709.  
 
The Paeonies.
Messrs. Barr & Sons, King Street, Covent Garden, London, W.C., and Long Ditton, Surrey, as growers of hardy plants, &c., have over two acres devoted to them. On Staurday, June 23rd, notes were made of a number of fine varieties which they largely cultivate in their nursery at the address just given. 
Singles.—The singles are varieties of Paeonia albiflora...
Gertrude is a sweet pink variety... 

Magazine  (15 Jun 1895)  Page(s) 668.  
 
Messrs. Barr & Son's Paeonies.
Single Flowered Sorts.
Others which well deserve honourable mention, but upon the merits of which space forbids us to descant, are Duchess of Portland, soft pink, frilled white; Gertrude, brilliant rose pink, of exceptionally fine form; Beauty, bright rose, shading to pink; Rosy Dawn, large snow-white flowers, tinged blush upon first opening; and Kaiser, brilliant rose.