Tell us more about original condition of the plant (size, container/B&B, etc.); how/where/when planting took place; treatment/maintenance since planting. There are lots of variables, and all we know right now is color of foliage.
It was in a container when I got it, part of a re-leafing program from the extension office. Dug a good sized hole & planted it. Stayed green for about a month. Watered regularly, everything else around it looks great.
Jessaree, not to be a bother but we really need your definition of 'watered regularly' in regards to how much water, how frequently. I'm not an expert but given your climate (I looked up your town on wunderground) that could very easily be scorch. This occurs when it's just too hot out and the tips of the leaves get burnt because the root system cannot replace the water lost in the transpiration cycle. It is usually a product of intense heat, being a new planting, and/or not getting enough water.
OK, please bear with me. I actually have experience with this tree.
Just a quick note about the Burr Oak. It's a plant that prefers - actually requires - acidic conditions. I have had neighbors with them. I suspect that your Burr Oak has become chlorotic, in that it is not absorbing iron from the soil because it is "locked up"..
Is your soil ph high? Is it alkaline? Burr oaks have difficulty absorbing iron in that environment. Symptom - they turn yellow.
Have you had a lot of rain? I noticed that even some alkaline plants were turning yellow, and it was magnesium loss, but given your trees' tendency to become chlorotic in alkaline soil it may have added to the problem.
The solution, IF that is the case, is to add iron to the soil. My favorite product is Ironite, and it can be applied via granules or a hose end sprayer (I love the latter).
You are going to need to spray it to correct the soil imbalance a few times a season. But IF that is the problem amending your soil will correct the problem with periodic use.
Not necessarily - information/knowledge is the key to power, or at least resolution of difficult situation. I doubt it would be harmful in this situation, but the application of an acidifying agent could very well be lethal in some circumstances to some plants.
I can think of a handful of things to find out before going to the length of changing soil pH:
**How is soil draining currently? Well-drained (as in sandy soils) or does water stand (as in clayey soils)?
**Is it planted too deeply? Combined with poor drainage or overwatering, this could lead to yellowness prior to death.
**What does a current soil test reveal about pH, nutrient levels, structure, texture, organic matter? This is where known quantities can direct addition (or not) of fertilizations, pH adjustments, etc.
**What does examination of the root system of a container grown young tree reveal? A woody plant grown too long in a container situation can develop a malformed root system from which it often never recovers, and usually has a difficult time exploiting new rooting volumes once planted. That alone could explain the current situation.
As I mentioned above - there is a lot that is yet unknown. I'd recommend a thorough examination of the plant, and a comprehensive soil test. Applying chemicals may relieve a symptom but not contribute to long term health of a fine species that could grace a landscape for centuries.
I hope no one takes affront (including you, Sequoiadendron4, esp. since you hail not far from Pottstown, my place o' birth) at my offering of information or requests for same. I would as comfortably ask these same questions if we were standing face to face discussing the issue, or walking through jessaree's garden sipping a cold iced tea - or sweet tea, per your preference.
It is meant to be helpful, and it's based on experience with these types of situations over a lifetime growing plants; managing landscapes large and small; networking with a range of practicing professionals; and now a number of years here and other forums responding to queries for assistance.
What I don't like is not knowing the culprit - kind of like "take two aspirin and call me tomorrow". Too many gardeners get frustrated and give up when things don't go right or go easy. I'd rather be in the camp of "I now know why it died, and I'll not do THAT again" instead of the one where shoulders shrug and mouth "it just died."
Perhaps this is not relevant but I was corresponding with someone in Virginia about their re-landscaping their back yard and I assumed since she said the area was loadedd with limestone that the soil pH would be alkaline. She informed me that tho this is counterintuitive, limestone soil is acidic. I have no way to check this out but just putting my 2 very novice cents in.
Im interested because, I, too am growing a baby burr oak. I got it in a pot of daylilies in a swap, the giant seed already sprouting. Im so proud of it and DO NOT want it to die. Therefore, I am very interested in this discussion. Mine is in a pot and I am about to up-pot to a larger size.
I would solicit the input of the soil scientists in the audience to reply to the person in Virginia and the statement about counterintuitiveness. I would certainly not go to that person regarding advice on growing plants - as it too may be counterintuitive. I'll take my growing recommendations based on sound science, lengthy experience, and soil tests from reputable labs - thank you very much.
Everyone is welcome to look up information about Quercus macrocarpa and its soil preferences and predilections. One will find that it grows in a lot of places - sour and sweet - and in a relatively wide range of climatic moisture regimes and temperature ranges. It is a great plant, and knowing its provenance will start to answer some of the questions asked here.