This cultivar discussed in “Hydrangeas forAmericanGardens” by Michael A. Dirr. He says that ‘Shannon’ is a double with up to 20 sepals per cluster, double clusters are not densely borne, creating an open inflorescence, more     upright than those of ‘Snowflake’. It has a compact habit, 4 feet high and wider than tall.   Introduced by the late Theodore Klein,Crestwood,KY.This cultivar was discussed at the 2003 Southern Plant Conference.

Gardens found in the 10 surveyed in 2010: HIL

UKPlant Finder 2012: Not listed