British Columbia: Stewartia monadelpha loosing leaves

Early this year I planted a Stewartia monadelpha in my back yard. The tree is planted in good, well draining, fairly rich garden soil. I've kept it watered weekly over the summer. It receives about 6 to 8 hours direct sunlight daily.

Around mid-summer, I noticed some discoloration on some of the leaves. It starts along the leaf veins and then spreads out. Eventually the leaf yellows and drops. The leaves remain supple throughout. This is now noticeable across the entire tree, so I am concerned about the tree's health. Any advice is much appreciated.

 

Start by digging around in the soil and making sure it is as moist as you think it is. This includes the field or potting soil the plant came in at time of purchase.

 

Thanks. I dug down and around and was surprised to see how dry the soil was right at the root zone. The tree received regular watering but obviously not deeply enough, especially with the recent dry spell. I assumed since the leaves were flexible, not crisp, it was not due to lack of water.

Does this explain the leaf discoloration?

 

Maybe. Meanwhile you found out it needs a good soaking anyway. Particularly when plants are installed with their original root system in potting soil there is a tendency for them to be vulnerable to drying out despite seemingly adequate rainfall or watering having taken place because of the often finer textured planting site soil having a greater attraction for water. This situation persists until the new plant roots out well into the surrounding soil, with diligent and aware watering being necessary to keep it alive until then.