https://www.pottertons.co.uk/pott/view_product.php?pid=3890I grow it outside in a few locations. Planting the scaly rhizomes about 6 centimeters deep, with the fine brittle white growth facing upward, taking care not to damage them.
It is very variable and there are a number of dark flowered forms that are worth looking out for.
E. B. Anderson grew this unusually well in his garden at Lower Slaughter in Gloucestershire, and in his book “Seven Gardens” he says;
‘It is important to top dress regularly, as the curious scaly roots will work up to the surface in the winter.’