i doubt its the preen ...

but i am sure.. that if you remove a foot of soil.. you will kill most of the trees feeder roots.. if not all of them ...

preen is a pre emergent .. i cant figure how it would affect lush new growth on an established old tree ...

i can find no reference to a swarf ....

could you favor us with a pic ... maybe for an Id.. thought the actual plant is irrelevant to the preen issue ...

i think i read the PNW ... is having one heck of a bad spring with wet and diseases .... are you in that area??? .. if only i could remember where gal said that ....

ken

Hi Ken,
Yes, I live in the PNW Seattle area. This particular tree also grows in very wet marshy conditions along the waterway near the University of WA. This is one of the reasons my landscape designer (who has since passed on) chose this specimen. In our yard it is located in a consistently wet area.

I too couldn't find any information when I searched the web. I am enclosing a photo. I am sure you noticed I am a novice and appreciate any help.

Swarf? A typo for Dwarf? There are a number of dwarf Bald Cypress cultivars out there but none more or less tender than another that I'm aware of, but, depending on the origin, that could be the case. You may need to contact your county extension service to see if your area has some pathogen that Taxodium is susceptible should folks from the PNW not chime in. Neither the rain nor preen should be a factor.

tj