Does this look like sunburn or a bacterial problem?

[Apex37]

My oriental sweetgum recently started browning, but to me it looks more abnormal than your typical sunburn. I try and keep it well watered, with current temps in the 100s, it’s getting watered about 2-3 times a day.

Part of me is worried it might be a bacterial leaf spot, or something like that, and just want to be proactive since it’s already been a rough year for me. Good news is it’s been growing really good this year and pushing another set of growth.

Any thoughts?

 

[Wood]

I certainly don't have enough experience to advise on this, but a couple contextual thoughts/questions

• Is it happening only on new growth or leaves that have already hardened off?
• All over or only on the apex/exterior? Sunburn would mostly only happen at the apex/exterior
• Did you do anything particular recently that the tree might be responding to, besides the heat?

Did you consider fertilizer burn? I know Osmocote used to dump extra nitrogen when it was especially hot outside

 

[Deep Sea Diver]

We are starting to see a large number of water/stressed trees in the past couple years out here, Oriental Sweetgums, Alders and Maples are leading the pack.

Anyways it’s kind of a typically deciduous sunburnt, damaged cells /and/or water stressed situation in that part of the plant.

Once trees get stressed and weakened, powdery mildew and all sorts of other nasties come out to play on the leaves. Usually not something that will destroy the tree, but should be taken care of.

One could hit it with a 2 TBSP 3% H2O2 / Qt water frequently. This will knock it down, yet until the environmental conditions abate, not much will remedy the situation, except much more shade and misting.

Also a link on maples, many apply to OS too.

Good Luck and stay cool!
DSD sends

 

[Wires_Guy_wires]

When the edges burn first, what I think of is salt related/overfertilization stress combined with heat.
High nutrient amounts and warm weather can burn the edges of essentially every plant.
But also, the outer parts of the leaf are the oldest and longest exposed parts, so any sun damage would show there first.

Most fungal or bacterial issues show up as yellow spots, that would later turn brown, orange or black. They're usually located randomly over the whole plane of the leaf. MOST of the times, not always.

I'm not seeing any mildew, I think it's minerals from your water. Mildew would stay white and would be more or less water repellent, whereas minerals are easily absorbed into water and would become wetted when sprayed. A bit of peroxide wouldn't hurt either way.

 

[Shibui]

Also check that the soil is still accepting water. The longer a tree is in the pot the more roots fill the soil. At some stage there's no spaces left for water to soak in so the root ball gets drier and drier despite frequent watering. I've lost several trees this way and only discovered the reasons after doing autopsies after death.
If this could be the problem, soak the pot weekly to ensure it is wet right through at least once a week.

 

[Apex37]

Thanks all!
It’s mostly just apical leaves that were part of the first push. I’d be surprised if it’s chemical burn, but anything is possible. I back off to only fertilizing once every two weeks during summer. I have Biogold on the soil, but I just added that about a week ago and noticed this issue before that.
I think the sun has just taken it’s toll, and unfortunately, I don’t have the ability to put up shade cloth which would help. I moved it to a more shaded portion of the garden in hopes that’ll help. It was currently getting sun until noon, but direct sun in Texas summer can do a lot of damage.

It’s still fairly new in this pot (got repotted back spring 2022), so it should be fine in regards to actually getting water to the rootball. I make sure I water pretty thoroughly, making multiple passes till water is coming out a good amount from the bottom of the pot.

 

[Apex37]

For reference, this has been our temps. 98 next week will be a welcomed relief as we’ll have had 46 days at or above 100 degrees this summer.

 

[namnhi]

For reference, this has been our temps. 98 next week will be a welcomed relief as we’ll have had 46 days at or above 100 degrees this summer.
View attachment 504449

Hello neighbor. Am seeing 90s in the forecast... congrats

 

[Apex37]

Hello neighbor. Am seeing 90s in the forecast... congrats

Hahaha right? I think we will take any relief we can get.

 

[Gabler]

Hello neighbor. Am seeing 90s in the forecast... congrats

Hahaha right? I think we will take any relief we can get.

I'm glad we're past that hot part of the summer here. It'll stay hot through the end of August, but only moderately hot, with forecasted highs in the low to mid 80's. It'll probably be 2024 before we get up to highs in the 90's again, though September can sometimes bring a late heat wave.

 

[namnhi]

I'm glad we're past that hot part of the summer here. It'll stay hot through the end of August, but only moderately hot, with forecasted highs in the low to mid 80's. It'll probably be 2024 before we get up to highs in the 90's again, though September can sometimes bring a late heat wave.

We still have 107 in the forecast next few days. I never thought I would say 90s is lovely