Magnolia dying bit by bit

[Bermy]

Here in Tasmania again...

A smallish magnolia, only about 8', apparently was planted about 11 yrs ago.
It started to go back, branches started to die one by one, tip down. It didn't see this stage.

Right now it has one small green branch left, trunk shows green under the bark and has more little epicormic buds starting to show (its still spring here)
The HO cut off the dying branches and leader, only two are left, low down on the trunk completely brown and dead now.

Now, down at the roots it is obvious that the plant was potbound when it was planted, the roots are going round in a circle, probably some girdling going on.

So can root girdling be solely responsible?
Other trees in the area, Robinia, look fine, it was a wet winter...

 

[flushcut]

Yes it is possible I just removed an ash that was all choked up.

 

[Mr. Sir]

The girdling probably stressed it enough to make it more susceptible to secondary problems, like armillaria or verticillium wilt.

 

[treelooker]

Now, down at the roots it is obvious that the plant was potbound when it was planted, the roots are going round in a circle, probably some girdling going on.

So can root girdling be solely responsible?

Yes most definitely--often sgr's cause dieback without pests involved. Perhaps clip the worst of the girdlers now and more in the fall--March?

 

[Bermy]

Thanks chaps...no sign of mycelium or fruiting bodies...how would verticillium wilt present on a magnolia?
I know what it looks like on a Phoenix palm...

 

[Mr. Sir]

Look for a brownish staining of the sapwood on suspect limbs.

 

[Bermy]

Hmmm, that's what the HO said she saw when she cut off the dead limbs...I've only gotten to see it after she cut it, and all that was really evident was the nasty roots.

There are robinia close by...are they susceptible to verticillium as well?

 

[Mr. Sir]

Yes.

 

[Bermy]

'Ta...