Just read through this thread. Should have asked my questions here.
We currently have eight different Brunnera cultivars in our mixed perennial beds, most of them we've had for over three years (includes Brunnera Variegata (apparently = 'Dawson's White')).
I've never noticed reversions in any of our Brunnera until this year and this year, for the first time, I'm just noticing reversions back to the species in two of our three 'Dawson's White'.
Richard Hawke (the Plant Evaluation Manager at the Chicago Botanic Garden) has said that they've probably spent more time removing reversions from 'Dawson's White' than from any other cultivar.
Has anyone else seen reversions in their 'Dawson's White'/Variegata? If so how successful was your method for removing the reversions before they overwhelm the cultivar? Apparently, pinching out the reverted leaves is one approach and dividing the plant with teasing out reverted parts is another.
I've also read that stressed 'Dawson's White are more likely to show reversions than other Brunnera cultivars. In our case, I would have though our two reverters are in a better location than the one non-reverter. Although we've been watering the garden through this very dry summer, the non-reverter is in a location which dries out quickly. At the same time, is not showing much new growth.
The reason I've just noticed this is that our spring perennials are largely hidden by our taller perennials through the summer and I accelerate cutting things back at this time of year to get light through (also to stop powdery mildew spores from overwintering, etc.).
Picture this Sept 16.