Dogwood dying

[Belinda]

I have a dogwood tree (Cornus Capitata) in my garden that looks as though its got a disease. It is late spring in New Zealand so it should have pale yellow bracts at this time, but many of the leaves on the tree are turning yellow and dropping off. Do you know whats happening?

 

[tshanefreeman]

It is very difficult to diagnose over the internet..................even with the aid of pictures, the problems can remain a mystery!

If the leaves are appearing chlorotic (yellowed) and are prematurally dropping, it is easy to believe that your dogwood is under stress. But from what?

Drought?
Excess Moisture?
Construction Damage?

The variables are countless..................yet, the answer is most likely there somewhere.

Perhaps a little more information about past history of the shrub's location and whether or not any changes have taken place over the last while could help us understand your problem more.

 

[Sylvatica]

I am not fully up to speed on pathogens of your area, but if that cornus were in my region, I would do as tshane suggested, clear excess soil/mulch from the soil-stem area, and test for verticillium and nectria, as a start anyway.

 

[coffeecraver]

How long has the tree been planted?It may have been planted too deep. Can you see the trunk flare?
Sounds like the roots may be girdled,

Sometimes girdled roots don't show up for a long time.

Has anything new happened in the area?