dtd, I'm sorry to hear you are having problems with your trees. You must be so disappointed after 10 years of waiting for them to gain some height. I've never heard of a 'Willow' Oak, but like all oaks, I would have thought they were pretty bullet proof. That's odd. Are they marginally hardy for you?

I haven't had similar experience I'm afraid. I wonder though about the Mass Extension Program. I think they accept samples of leaves that they can determine what type of disease something has. Sounds like you had no indication of disease on the Oaks though, right? But the next time you see a suspicious problem with leaves, you could send it off for identification.

The only other thing I can think of is to call a local nursery and describe what happened and see if they have any ideas.

Last year, I had a self-seeded maple seedling die in an incredibly short period of time. Since the area it had chosen to live in is very close to a spring, and last years was not exactly the driest ever, I assumed the problem was wet. It hasn't spread to anything else.

Nan,
I started noting odd losses and partial losses in my yard last year and think what is happening is verticillium wilt or one of its close cousins that have been present in varying degrees in my wilt prone trees and shrubs all along and the very wet 2009 exasperated this disease.

My plan now that the surviving but ailing deciduous trees and shrubs are leafing out is to send of one maybe two specimens to Umass for testing. Although definitive this is a pretty expensive test ($50.00 + over night shipping charges per specimen). They do however suggest you call first for a possible phone diagnosis.

I am feeling that my penchant for moving things around has added to the wide spread problem on my property. I will be sure to share any future findings with you.

Here is a link that might be useful: UMass Tree & Shrub Diagnostics