is it deciduous??? best guess:.. something was wrong with this plant in the pot.. perhaps circling or girdled roots.. and it is struggling to get ESTABLISHED.. as fast as the others ... and due to such.. it suffered a worse summer than the others.. it simply could not cope.. short of digging it up.. and finding out whats wrong with the roots.. i doubt any any amount of fert or soil amendments is going to make a difference ... and frankly dumping either on mere speculation.. borders on pollution after a while.. you have to react to a crisis.. not really guess at a solution ... i would wait until late spring to see if it buds out with vigor.. and if not.. i would dig it up and find out why ... but you would probably be better off doing that now .. why wait ... and if its under warranty.. talk to the seller now ... ken

The leaves of evergreens in general are only meant to stay good/green/healthy for "X' amount of years...varies from plant to plant. When a plant is going into dormancy, it will often move some nutrients around and move them into the roots/stems/trunk of the plant...storing nutrients for next springs growth. "IF" this Pieris was planted and grown on the lean side (not much fertilizer or nutrients in the original root mass or new soil), it is possible to see more yellowing/leaf drop on the older leaves...just a natural cycling of the leaves. You can also see this on Pines in the fall,older/inner needles turning brown..... Schmoo

Me too...Mountain laurels and cherry laurels are both prone to soil born root fungus. Some of my dwarf mountain laurels were looking yellowish and unhappy, so I dug one up and it clearly had white spots of root fungus. Several others, which were quite well established, have the same problem. Only the ones planted on a pronounced slope are happy. I had used ground bark mixed with the native soil and had created a berm of soil with better drainage, but over time and with the frequent rains this summmer, it was not enough to maintain the great drainage they require. My instincts are to toss mine all out along with their surrounding soil. Does anyone know if they can be treated and relocated?

The most common cause of general yellowing of the foliage is excess water in the root area, which excludes air and causes the roots to be unable to uptake nutrients. I would do some digging to see what the roots condition is. Al