Dogwood turned brown
One of my Kousa Dogwood trees just turned completely brown (see photos). I presume it is dead or nearly so. For my edification - what do you think happened? Is there anything i should do to prevent same for the other kousa dogwood? Can i replant a new dogwood (or maybe a regular old flowering dogwood vs kousa) in its place? Background: The trees were planted about 5 or 6 years ago. Both are at the edge of wooded tree line (mainly oaks, a few gums, etc) where they get some (maybe couple hours) afternoon/ late afternoon sun. The trees do get water (irrigation system) -- but i don't overwater. I use pine straw mulch in the garden bed and there are other shrubs/ perennials in the same garden area. The trees have never been spectacular; and last year i noticed a few branches on each tree lost all its leaves (maybe had anthracnose but i am not sure). This year both trees did bloom and leaf out and had buds. So i thought they were recovering. Then suddenly in early July (seems like it happened the week i was on vacation ) the one tree just turned brown. In the second photo, i noticed that a few of the leaves of the willow oak behind/ above the tree also have some brown leaves-- is that a coincidence? Any insight you can provide will be most appreciated.
Once a tree has declined it is difficult to determine why. Possible reasons include a type of root damage such as voles feeding on the roots, http://extension.umd.edu/hgic/voles, poor drainage, too much moisture, planting too deeply, excessive mulch, etc. we cannot say for sure. See our publication on these types of problems
If you remove the tree, look at the root system. Make sure the roots are not black and mushy or they have not been eaten by voles. Make sure it is not planted too deeply. You should be able to see the flare at the base of the trunk where it joins the root system. Kousa dogwood is not susceptible to anthracnose.
At this point, if you want to replant, consider a native dogwood. Do not plant in the exact spot but several feet away. Take a look at our publication for powdery mildew resistant varieties. Dogwoods are best planted in the spring and grow best in morning sun and afternoon shade. http://extension.umd.edu/sites/default/files/_images/programs/hgic/Publications/HG12_IPM_Series_Dogw...
See our planting process and post planting care. http://extension.umd.edu/hgic/trees-and-shrubs/planting-process