Large or very large lavender blue flowers with a darker bar and deep red anthers on white filaments, sometimes semi-double. Raised by L Späth, Berlin in 1891. The variety has received the Royal Horticultural Society's Award of Garden Merit.

There is much confusion about whether this is the same cultivar as 'Xerxes'; The International Clematis Register and Checklist 2002 is adamant that it is not. 'Xerxes' was raised by Noble in 1877 and has a separate entry on this website.

Group:	Early large-flowered group
Approximate height:	2.0 - 4.0 metres
Flowering period(s):	May Jun Jul Aug Sep
Aspect:	Any aspect
USDA zones:	4 5 6 7 8 9
Pruning:	Light prune (Group 2)
Raised by:	L Späth
Country of origin:	Germany
Date raised:	i1891
Parentage:	Unknown
Other name(s):	'Elsa Spath'; 'Elsa Spaeth'; 'Else Späth'; 'Elsie Spath'; BLUE BOY™ in Australia (not to be confused with the 'Blue Boy' which is a viticella type).
Further detail:  Flower diameter: 14-20 (-22)cm Tepals: 6-8; 7-9cm long, 4-5cm wide, rounded, overlapping, pointed Click here for the text of an IClS article about this clematis Database entry: 158