Article (magazine)  (Jan 1955)  Page(s) 58.  
 
Alphabetical Check List of Tree Peony Names In  Public Collections And/or Available in Nurseries 1954-1955
Japanese, Crimson, 'Koku-ho' or 'Koku-how' (Black Bird) (Jap. bef. 1929), [Gardens] Scott Foundation, [Nurseries] Oberlin Peony Gardens

Website/Catalog  (1941)  Page(s) [3].  
 
Tree Peonies
Kokuhow (Black Phoenix). Large; double; luminous, clear blackish-red...$8 00

Website/Catalog  (1939)  Page(s) [1].  
 
Tree Peonies (Pæonia arborea)
Japanese Tree Peonies 
English translation in parentheses
42. Kokuhow (Black Phoenix). Large; double; luminous, clear blackish red; well-arranged petals... $8.00