I have three of these eye-catching trees that are becoming a nuisance. They are last to leaf in spring first to drop in fall. They suffer major die-back each year and drop leaves steadily all summer. I am constantly sweeping up after them and am ready to remove them. Does anybody have a clue what is wrong with these trees or are they just messy? I can find no pest or disease in the leaf litter and the branches are so high now it is difficult to get to the source. Does anyone know if this species is prone to verticillium wilt? Thanks for any help in saving these trees.
Dieback would tend to indicate a pathogenic infestation or other abnormality. Otherwise summer leaf drop would probably be the result of drought conditions. Perhaps you have both.
In my limited experience, these plants just suffer from a general lack of vigor, as is not uncommon among yellow- or variegated-leaved varieties. Some of the problems you describe -- late leafing-out and early leaf drop -- are characteristic of the species, R. pseudoacacia (at least in my area). But when you add on top of that the more temperamental nature of the 'Frisia' clone, then you've got a finicky sort of fellow. I'm on my second 'Frisia' now, and I've got it planted in what I hope are nearly optimal conditions. I lost the first one years ago. It never really thrived, suffered annual die-back like you've described, and one year just never came back at all. I think maybe it wasn't getting enough sun. Or I don't know, maybe it was just too far removed from the blessed British Isles, where these things seem magically successful.
One my neighbour planted grew 3m year before last (2006) after it was pruned a bit. Not so much more last year or this year, though. And it doesn't drop all its leaves until quite late, mid November or later.
