Book  (2010)  
 
p92. Peter Harkness. An Update on Persica Hybrids.
....it was decided to introduce four of them, rather than see them perhaps lost for ever.
Euphrates [HARunique] (R. persica x 'Fairy Changeling') was pollinated in 1980, introduced in 1986, and carries small, single salmon rose flowers on bushy low plants. Scarlet 'eye' fading purplish.

p95. ....In comparison with 'Tigris' Euphrates had so far proved mulish and defeated everyone's breeding efforts. Jack suggested to the Dutch breeder Peter Ilsink that he might like to try his luck with it. Peter was highly successful, and in 1997 introduced 'Euphoria', a beautiful spreading shrub with sprays of yellow blooms rimmed orange-salmon. Peter has raised other beautiful Persicas in a variety of colours, single or semi-double, all with the 'magic eye'. His 'Babylonia' series is marketed in Japan.

Website/Catalog  (2007)  Page(s) 33.  Includes photo(s).

Book  (Dec 1998)  Page(s) 228.  Includes photo(s).
 
Euphrates (HARunique) Modern Shrub. Harkness (UK) 1986. Description... pale salmon-pink flowers with a deep pink eye... performs best in hot, dry climates and lighter soils...

Book  (Apr 1993)  Page(s) 166.  
 
Shrub, pink blend, 1986, (HARunique); Hulthemia persica x Seedling; Harkness. Flowers pale salmon red, deep pink eye, single (5 petals), small blooms in clusters of 3-9; slight fragrance; foliage small, variable form (usually long and narrow), light green; prickly stems; low, spreading growth.

Book  (Feb 1993)  Page(s) 261.  Includes photo(s).

Book  (1992)  Page(s) 30.  
 
(HARunique) Persica hybrid; salmon rose, scarlet at petal base; bears clusters of many small single blooms; not remontant; growth hummocky, 24 x 30 in (60 x 75 cm); leaflets vary in shape; little scent. R. persica x 'Fairy' Changeling; Harkness 1986.

Book  (1991)  Page(s) 261.  
 
Euphrates (HARunique) Modern shrub. Parentage: R. persica x 'Fairy Changeling'. England 1986. Description and cultivation... The flowers are five-petalled in an unusual salmon-pink colour with scarlet at the petal bases...

Book  (1988)  Page(s) 8.  
 
[In his foreward to this book, Peter Hering writes:] 'Tigris' and 'Euphrates' … have been created by crosses with Rosa (or Hulthemia) persica, a strange plant that has sometimes been included with the Rose family and sometimes put in a genus of its own. Work with persica is difficult and has rarely been attended with any success. These two varieties represent a very significant accomplishment for Harkness & Co.

Book  (1988)  Page(s) 54.  Includes photo(s).
 
Description. Jack Harkness and Alec Cocker used R. persica in their breeding program. Their objective is to fuse the genes of R. persica, a remote wild cousin of the rose family, into garden roses. Its attractive features are a bright non-fading yellow colour and the presence -- uniquely in wild roses -- of a rich scarlet 'eye' at each petal base…. Together with 'Tigris', which is yellow, it points the way forward to exciting future developments in rose colours.

Book  (1985)  Page(s) 166.  
 
The most interesting project was Rosa persica, a difficult species, of which I probably held the largest stock ever grown outside its native regions. The object here was to raise a fertile hybrid, but although we got in the end over a hundred, some very beautiful, and notable as the first recorded since 1836, they were all sterile and bloomed only in the summer. Their beauty lay in a dark red eye at the centre of the bloom. I obtained them single and double, yellow, pink, salmon and orange. Having put a lot of work into this bit of pioneering, I thought we might introduce two of the hybrids, and sent them to the Royal National Rose Society's trials. No interest was expressed, and I accepted the fact that they were not yet suitable for gardens, although of great botanical interest.