I purchased and planted five Kerria japonica ‘Honshu’ from Greer Gardens in 2010. They matured and performed beautifully in my shady woodland garden. Last year however, at the end of the season one plant dropped most of its leaves. This year, after flowering, two Kerria ‘Honshu' completely defoliated and virtually all the stems are brown. And now the other three are in varying stages of leaf drop. A Kerria japonica ‘Picta’, not located close to the ‘Honshu’, also is showing the same symptoms. The K. ‘Honshu’ are growing in full to part shade; the K. ‘Picta’ gets full afternoon sun. Dirr lists leaf and twig blight, canker, leaf spot and root rot as possible problems but says he has never noticed anything serious. A web search yielded references to a destructive blight (especially in the U.K.), and this note on the Morris Arboretum site: “A destructive stem blight is making Japanese Kerria more difficult to find in the nursery trade.” Recommendations include cutting the plant to the ground, and possibly digging up all roots as the blight can infect the roots as well. I also am concerned about this potential pathogen affecting other plants in the vicinity of the Kerria ‘Honshu.’ According to the 1982 Kent County (MD) Soil Survey my soil is Fort Mott loamy sand (FMC2), an unusual soil type for Kent County, as it occurs in only two locations that I could find. Our soil is acidic, in the range of 4.2 - 5.0 pH. According to 2012 soil tests interpreted by Dr. Frank Gouin, my soil has severe nutritional problems: magnesium levels greater than calcium levels, phosphate levels higher than potassium levels. In 2012 we applied gypsum, potassium chloride and calcium nitrate per Dr. Gouin’s instructions, but have not amended since. We do not use pesticides or fertilizers, and the Kerria ‘Honshu’ have not been mulched. The Kerria ‘Picta’ is mulched with composted arborist wood chips. I have included three photos: Kerria1.jpg shows a completely defoliated and brown Kerria japonica ‘Honshu’. Kerria2.jpg shows a Kerria japonica ‘Honshu’ in decline. KerriaLeaf shows affected leaves on the declining K. ‘Honshu’.