September 2013 issue of the Cornell Flower Bulb Research Program Research Newsletter:
In the last newsletter, I mentioned that bare roots of Agapanthus ‘Blue Triumphator’, ‘Donau’, ‘Dr. Brouwer’, ‘Elisabeth’, ‘Pinnocchio’, ‘Polar Ice’ and ‘Sunfield’ were planted in our zone 5b outdoor
perennial trial facility in Ithaca in mid-summer of 2011. No special winter protection was given, other than the usual 5 cm of mulch that was applied when they were planted in the summer, and
it should be mentioned the site has very well drained loamy soil (no excessive winter wetness!) After the winter of 2011-2012, every single plant survived, and most flowered.
Read the whole article. Starts on page 4.