10-year-old Little Gem Magnolia not looking well. What to do?

[creaghzy]

I have several Little Gem Magnolias in my yard that have just been rock solid for about 10 years now. One has started looking not so great this year. I have had someone who claimed to be an arborist come out about 3 months ago to look but he said he had no idea and maybe I should let them inject it with fertilizer. I didn't feel confident about that answer but have not been able to diagnose with google and don't want to put the wrong treatment on my tree. Hoping the group here can help me figure this out. I am adding photos. Part of the tree looks just fine but the other side has several branches that are now just empty sticks that need to be pruned out. When you look out at the Magnolias from across the yard, this one looks thinned out compared to the others. I took pics of some of the leaves on the ground and you can see they look sort of mildewed. I am desperate to save this tree and make sure whatever it is doesn't spread to my others. Any help would be so gratefully appreciated. (one pic shows the tree in full, one shows the part with the empty branches, then the leaves on the ground.)

 

[JeffGu]

Is all that soil/compost mounded up above the root flare?

 

[creaghzy]

I am posting pics of the base of the tree from 2 different sides. The compost is much thicker away from the base, but hopefully you can see enough from the pic to advise if i need to remove more from that area. Many thanks for your time.

 

[ATH]

Yes...you need to remove more. You should see clearly where the trunk flares out into structural roots.

 

[JeffGu]

Well, that all looks like it was piled on there after the trees were planted. I'd get that away from the trunks by 8-12" and get back down to the root flare. That's just going to encourage girdling roots, which will kill back parts of the tree. I don't see any Magnolia Scale or black, sooty mold in your pics.. which is good... but it does look like it's got a fungal leaf blight of some kind. I'd rake up any leaves that have it on them, burn them or dispose of them.

You probably should take some affected leaves from off the tree, not off the ground, and see if a local nursery or county extension office can identify the fungal infection and recommend a treatment. Magnolias are tough buggers, but they are susceptible to leaf spot and blight... and expecially to Magnolia Scale (which yours don't appear to have from the pics). We don't see that particular variety this far north, except as potted houseplants, but most varieties respond well to treatment and rarely die.

Cladosporium and Septoria spotting are both common in the magnolia trees around here.

By the way, those are good pics... very helpful. Some folks post a pic taken from a block away, which is not so helpful.

 

[sb47]

Pull that mulch back off the trunk past the drip line. It also could use a good pruning. I would prune it up past the fence line. Those lower limbs are just taking up yard space and will continue to grow away from the fence.