‘Silver Frost’ is a hybrid cultivar from a back-crossing of ‘Lochinch’ (Buddleja fallowiana × B. davidii) with an unnamed cultivar of B. davidii. In all aspects it resembles B. davidii, except for the foliage which is more glaucous. (Pers. obs.).
USDA Hardiness Zone 6-9
RHS Hardiness Rating H5
This hybrid was raised by Prof. Michael Dirr and his team at the University of Georgia, USA, in the late 1990s. It is a fast growing shrub reaching just over 2 m in height and has excellent silvery to grey-green foliage. The inflorescences are short by modern standards, averaging only 20 cm in length. The flowers are white with a yellow eye.
Growing conditions are the same as for all B. davidii cultivars and hybrids: a rich and free draining soil which doesn’t become waterlogged in winter, in a position in full sun for at least a part of the day. ‘Silver Frost’ is currently only cultivated in North America and has not been introduced into Europe (Stuart 2006; Hawke 2015).