One of my red oaks has always seem to struggle compared to its bigger sister next to it. The leaves are often a lighter green and showing veins. This spring I've noticed a lot of black specks in the leaves which is likely a fungal infection from all the rain we have been having (Round Rock area).

This morning though I noticed a bright yellow slime mold on the bark. Is this two different infections? Do you think this will clear up when we get to hotter, dryer weather?

I believe mulch should be kept a few inches, around 4 or so, away from the trunk.

The mold is probably no big deal but I agree that perhaps the mulch could be pulled back some.

How long ago did you plant the tree again? Did you wrap the trunk to protect it from sunscald? Red oaks are susceptible to that and it can cause the bark to peel and crack which can lead to insect damage from borers.

The lighter leaves is tougher-sometimes that can mean an iron deficiency, but if the other tree is fine then perhaps not. Red oaks do have several fungi that they are susceptible to, so you could take a few leaves in to your county extension agency and see what they say. In the mean time, some possible things to try are a little fertilizer to give it some new growth or even having your soil tested to see if it is deficient in something the tree needs. Neil Sperry or one of the other plant guys had a column once about nurseries sometimes mixing up pin oaks and red oaks and apparently the pin oaks struggle if the soil is too alkaline.

That's all I've got. Best of luck to you!

Edit-I left off applying a fungicide because you might want to try encouraging the new growth first and see if the drier weather clears things up.

How old is the tree roughly? I have two 1 year olds wondering how long before they get close to that hieght

Oogway said:

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The mold is probably no big deal but I agree that perhaps the mulch could be pulled back some.

How long ago did you plant the tree again? Did you wrap the trunk to protect it from sunscald? Red oaks are susceptible to that and it can cause the bark to peel and crack which can lead to insect damage from borers.

The lighter leaves is tougher-sometimes that can mean an iron deficiency, but if the other tree is fine then perhaps not. Red oaks do have several fungi that they are susceptible to, so you could take a few leaves in to your county extension agency and see what they say. In the mean time, some possible things to try are a little fertilizer to give it some new growth or even having your soil tested to see if it is deficient in something the tree needs. Neil Sperry or one of the other plant guys had a column once about nurseries sometimes mixing up pin oaks and red oaks and apparently the pin oaks struggle if the soil is too alkaline.

That's all I've got. Best of luck to you!

Edit-I left off applying a fungicide because you might want to try encouraging the new growth first and see if the drier weather clears things up.

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Thanks for all the replies!

This tree was planted about 4.5 years ago by the builder. I haven't heard of wrapping it, but if it's something that should have been done, then I know the builder's landscaping guys didn't dot it. I've had to fix everything they've done from fencing, leveling the yard, and sprinkler system stuff.

Yea, the leaves were harder to diagnose. It's also difficult because the red oak right next to it has always done well with dark green leaves and it's probably the tallest red oak in the whole development. This one has always seem to struggle a bit, but has still been pretty healthy until this season. I have put down fertilizer and ironite this season, so I'm probably leaning toward some type of fungal infection in the leaves. Good idea about the county extension though, I bet they know.

Texker said:

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I don't know if it will solve all your problems but there's no root flare showing. I can pretty much guarantee that's a significant part of the problem. Pulling the mulch away as others have mentioned will definitely help, but if the tree is planted too deep you must very carefully remove some soil from around the base of the tree to expose the root flare.

Check this out for a great explanation of why root flare is important.

https://www.heartwoodtreecompany.com/blog/ho2oiebnedkg6rozdn75azih6bgghm

Also from the pic it looks like you are using cypress mulch. You'll need some mulch just not on the root flare . I suggest switching to native texas red cedar like this one: https://www.lowes.com/pd/2-cu-ft-all-natural-medium-brown-mulch/3120081?cm_mmc=shp-_-c-_-prd-_-lwn-_-google-_-lia-_-179-_-mulchandstone-_-3120081-_-0&kpid&store_code=610&k_clickID=go_1792976560_68785407749_346853825249_pla-698747504388_c_9026842&gclid=EAIaIQobChMI8fCq9viw4gIVEtvACh2Cvg3bEAQYAyABEgL0v_D_BwE

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Interesting read, it definitely has the "pencil in the ground" look. The other tree definitely has a little more flare showing and probably explains why every year it tends to outdo its twin.

I'll pull some of the mulch back and see if that exposes the root flare a bit. The mulch is a cedar mulch I get from Lowes, but when I looked it up on your link, it says cedar "blend" mulch. I don't know what the hell that means, it looks and smells like cedar when I put it out. May have to switch to the one in your link.

Thanks!

I'll second the Texas Native cedar mulch. Very fragrant, well shredded and really forms a great weed barrier and maintains color for longer than any other mulch.

philsfog said:

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How old is the tree roughly? I have two 1 year olds wondering how long before they get close to that hieght

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Both the red oaks in the front yard are about 4.5 year old trees from planting. I will say, A LOT of the red oaks in the neighborhood look like crap because people don't take care of the their yard. I mean some of them look like midgets that have hardly grown in years. I'm not the best about trees obviously, but I'm pretty adamant about keeping the turf looking good, which has helped the trees I think. I put down some high nitrogen fert once a month in the growing season, but in between that I usually will put down something organic or milorganite to keep the soil microbes and worm population healthy. I'm careful not to over water as well.

Here is the other tree next to this one, same age. They are pushing twenty feet or so at this point. You should keep them trimmed better than I have though.

SoulSlaveAG2005 said:

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Yellow slime mold is probably from the wood mulch. Actually pretty cool/gross stuff. But you shouldn't worry too much about it.

I'm not sure on the black spots but it does look like the mulch is too high on your trunk. Need to pull that away some. Tree may be planted too deep.

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That slime mold is interesting. It's already gone from a bright yellow to a dull orangeish color within a day. I think it had just happened over night when I first posted. From what I can tell, it's not too concerning, but I was worried I had two different infections going on which could kill it.

Thanks for the help.

More than likely a pin oak.
[url]https://neilsperry.com/2017/04/identifying-treating-iron-deficiency-in-plants/[/url] (scroll down)

[url]https://neilsperry.com/2016/11/trees-for-fall-color-shumard-red-oak/[/url]

Thank you for posting a pic of the two trees together.

The builder planted the trees closer together than IMO is preferable for optimal health. That doesn't mean that is why the smaller one is struggling, but it may have a harder time keeping up as it competes for resources. We have a red oak and they are a pretty tree.

Oogway said:

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Thank you for posting a pic of the two trees together.

The builder planted the trees closer together than IMO is preferable for optimal health. That doesn't mean that is why the smaller one is struggling, but it may have a harder time keeping up as it competes for resources. We have a red oak and they are a pretty tree.

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they don't care. there's probably an HOA development rule that says 2 trees must be planted.

Agreed, but sometimes one can make the decision with respect to keeping one tree that may linger into a slow decline and require time and $$ or replace it with a more suitable specimen that is spaced more appropriately. An example might be an understory tree that doesn't grow as large as an oak. That way you still have two trees but one is the large shade providing specimen and the other doesn't compete in the same way.

Quote:

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...planted the trees closer together than IMO is preferable for optimal health.

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Don't tell that to the forest!

^^Haha! You got me!

OP, one thing you may wish to examine on your tree that is larger: In the distant shot, I can see that it has leaves that are lighter in spots as well. When I examine your closeup leaf on the ailing tree, I am noticing that the veins are green but the leaf is yellow/lighter. That seems a lot more like the iron chlorosis. The suggestion to have the extension agency chime in may save you some time and effort in the long run, especially if those trees are not suited for alkaline soils. That doesn't mean you have to take them out, but it does require some care for them to keep them healthy and I'm seeing mixed opinions on the outcome long term. I have a very difficult time comparing the leaves of pin and red oak, but looking out my window right now at our tree which is in about as alkaline clay as it gets, the leaves are a nice solid green.

Good luck to you!

ftworthag02 said:

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More than likely a pin oak.
https://neilsperry.com/2017/04/identifying-treating-iron-deficiency-in-plants/]https://neilsperry.com/2017/04/identifying-treating-iron-deficiency-in-plants/(scroll down)

https://neilsperry.com/2016/11/trees-for-fall-color-shumard-red-oak/]https://neilsperry.com/2016/11/trees-for-fall-color-shumard-red-oak/

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You would be correct, thanks for clarifying that. I think I had it in my mind for so long these were Shumard red oaks, I didn't really consider the possibility for them to be a pin oak. We have a lot of red oaks in the greenbelt behind the house and it's pretty easy to tell the difference now.

Them being a pin oak would sort of explain the yellowing if in fact there is an iron and alkalinity issue in the yard. We are kind of in an interesting area for soils as east of here is typically heavy clay soils rich for farmland and west is the beginning of the hill country with lots of limestone deposits. I don't think pin oaks do well west of here. What's interesting is the difference every year between the two trees despite being 15 feet apart.

I'm not overly concerned as we are moving soon, but I definitely didn't want one to die on me right before we try to sell.

Thanks for all the help everyone.

Based on your description, it does sound like you're seeing multiple issues affecting your red oak. The lighter green leaves with visible veins may indicate a nutrient deficiency, root stress, or even early signs of chlorosis, especially if the neighboring oak is thriving in the same conditions.

The black specks on the leaves are likely a fungal leaf spot, which is fairly common after extended wet periodsespecially in the Round Rock area with all the recent rain. This usually isn't fatal, but it can stress an already struggling tree.

The yellow slime mold on the bark is unrelated to the leaf fungus. Slime mold is a harmless organism that feeds on decaying organic matter; it doesn't actually infect the tree, though it can look alarming. It often disappears when the weather turns hot and dry.

That said, the combination of symptoms points to an underlying stress issue that may worsen without support. We recommend a tree health inspection to evaluate soil conditions, drainage, and potential root zone issues. With proper diagnosis and care, including possible fungal treatment and soil amendments, your red oak has a good chance to recover.

Alex
https://treeservicealexandriava.com/

Black thumb's 2-cents:
The light green leaves are smaller twin of proud neighbor's "Red Oak" as tagged in nursery but "Pin Oak" reported by Picture This photo input - twice.

He pampers his tree with city water during droughts & yes, has a Post? Oak large North neighbor at distance similar in scale to your photo.

Aggieland volatile clay soils topping a deep shale layer and city sodium tap water ... all of which drives Kyle Field/TAMU grounds caretakers nuts as per latest radio interview.
I think neighbor & others have reported grand results with
Drill holes 12-24"d just outside the drip line perimeter
Fill with 13-13-13 + sulphur (the mix varies with the reporter, so read with a grain of salt)
Water well in well, rainwater best