Website/Catalog  (1930)  Page(s) 24.  
 
Single Peonies.
The single varieties are becoming very popular as they become better known. They are more early in season and very attractive.
85 Black Prince. Thurlow. Dark garnet, not glossy. $3.00

Magazine  (Aug 1923)  Page(s) 269.  
 
"The American Peony Show at St. Paul" by Edward Auten, Jr.
...The Thurlows had a large and striking exhibit of singles and Japs, wonderfully fresh to have come so far. The outstanding kinds were Sophia Houston; Purity (Bunting); Eglantine, which was shown in most exquisite color; Black Prince, a fine deep red, with a good mass of yellow stamens, and green carpels which do not spoil the effect as the red ones do in so many varieties. 

Website/Catalog  (1916)  Page(s) 5.  
 
Single Herbaceous Peonies
Black Prince (Thurlow), a seedling of our own growing, very dark garnet with a mass of golden stamens, soft, rich coloring, not glossy. Not for sale.