I agree with Jean. I would use a very well draining mix. I use EB Stone's Cactus Mix, but there is also a good recipe on our forum to "511" mix or "gritty" mix that you can search out. Definitely needs to be repotted, and the roots straightened out if you see they're circling in this small pot. Also, I would consider switching fertilizers. 4 fertilizer applications a year for a container citrus is not nearly enough. Fine for in-ground citrus, but not for container citrus. I would consider using Dyna Gro's Foliage Pro, and use 1/2 strength with every watering. And, I would also supplement with Osmocote Plus (it must be the "Plus" formulation so you have the best NPK ratio along with all the micros, very important). Your tree is in bad shape. I would expect after re-potting and correct fertilizing and watering that you'll see these old leaves drop, pushed out with new flush. Patty S.

This sounds like a case of transplant shock which in part may have been caused by putting in an oversized tree. I doubt all the roots originally grown came with the tree and it may take one or more years for the tree to adjust and compensate. At least, if the growth isn't scorched looking and is only dwarfed, it sounds like the care you are giving is adequate. I think you just need to wait this out. You know, red oaks are very fast growing. You probably could have opted for a smaller tree and gotten the results you wanted for screening rather quickly.

Ditto above. I am quite familiar with these trees and had 4 large Norways removed from my lot, with 1 huge one remaining, which is the biggest. :( They are extremely weedy, and have started to invade the small woodland areas in the neighborhood. I cut, poison, and girdle these suckers at every opportunity and am still debating removing the last big one which is indeed a beast ($$$). Acer platanoides 'Crimson King' is a very common cultivar and may be less aggressive than the species. However, since it is a Norway, I would trash that sucker and plant a much nicer native tree instead (I hate Norways too).

it would be nice to know.. where you are. ... what zone... and if there has been any frost or freeze since the leaves emerged ... have you ever had a soil test done??? .. jean is suggesting something nutritional is way out of whack ... like pH or some such .... a call to your COUNTY extension office.. might get a quick answer if the soils in your area are generally bad in some regard ... ken ps: any chance the lawn was sprayed????