Book  (Oct 2001)  Page(s) 106-107.  Includes photo(s).
 
Clematis 'Alblo'
Herbaceous/Heracleifolia Group
Trade name: Alan Bloom
(C. 'Bressingham Bluebird')
Introduced by Blooms of Bressingham (England) early 1990s
First named 'Bressingham Bluebird' by Alan Bloom, the founder of the nursery, and later re-named in his honour for his 90th birthday.
Selected form of C. 'Wyevale'
... single, tubular, hyacinth-shaped flowers... four dark blue tepals, which expand widely towards the tips and strongly recurve, revealing white filaments and yellow anthers. The flowers become more mauve with age...