Michael Steinhardt Trident - Brown Spots

[MrG]

Folks,

I’ve read a bunch of these forums but I can’t decide which situation might apply to my tree. The specimen is a Michael Steinhardt Trident that I’m trying to develop. I haven’t had it long, and I don’t believe I am overwatering or underwatering, but it’s hard to tell as it’s still in a nursery pot. It is getting approx 6 hours of full sun per day. I am noticing progressing of these brown spots on the outer canopy and so I’m wondering if it simply needs more shade. See below for pictures of one day to the next, and you can see there are some new brown spots on day 2.



If it’s simply wear and tear from the Tennessee heat, no problem. I’m building a 40% shade cloth structure now. But if it’s disease or root issue, I’d greatly appreciate knowing how to help it succeed.

I topped the nursery soil off with akadama, trimmed it back after I got it about 2 weeks ago, and started it on biogold about a week ago. Photos of initial cutback below.




Any points I missed I’ll be glad to supply. Thanks so much for any help in advance!

All best,
MG

 

[Paradox]

Soil from above in the first photo looks like akadama. It also looks pretty yellow, not sure if it's just new leaves or the lighting in the photo.

Not sure about the brown spots. Has it been raining a lot? It could be fungal or a nutrient deficiency

 

[MrG]

Soil from above in the first photo looks like akadama. It also looks pretty yellow, not sure if it's just new leaves or the lighting in the photo.

Not sure about the brown spots. Has it been raining a lot? It could be fungal or a nutrient deficiency

Thanks! It is indeed yellow - this cultivar is a yellow trident that turns to orange.

And yep I topped it with akadama as the soil was low. The bottom photos anre outdated and I poured it out and changed to all akadama.

It did rain the past several days yes, but not like insane amounts. But it did not dry out as much as one would wish.

 

[Betula1]

As its a yellow cultivar then the its almost certainly caused by sun-scorch ,which occurs in many yellow leaved plants when exposed to hot sun, so keeping it partially shaded will help.

 

[MrG]

As its a yellow cultivar then the its almost certainly caused by sun-scorch ,which occurs in many yellow leaved plants when exposed to hot sun, so keeping it partially shaded will help.

This is really great to know - I hadn’t realized that. Thank you!

So then regarding the watering for a yellow leaf cultivar, are there any concerns of overwatering due to it not craving full sun/utilizing water more slowly, or anything like that? I have been assuming at least one good watering per sunny day is a good thing but again, this is my first maple and a bit particular.

All best,
MG

 

[MrG]

Posting an update here. I built a shade structure so today it did not experience the full sun. I suppose the reaction/correction will be gradual if that was the issue, but the spots are still worsening.


One question: I topped this off with 100% Akadama on top of nursery soil. So maybe the akadama is trapping moisture it shouldn’t given that it would usually not be sitting on top of nursery soil? Perhaps I should remove it and see what happens? That’s the only other significant change that’s occurred since I initially acquired the tree.

Thanks all,
MG