I have an 7 y.o. Arbutus Marina in a 1/2 wine barrel that is turning yellow (again). It was yellowish last year, but this winter (San Francisco Bay Area) it darkened up, but now is quite yellow again. I've just given it chelated iron. Is there anything else to do for it other than transplant it into the ground? Thanks -Howard
Might be a nitrogen deficiency due to cool winter conditions and/or getting too wet at the root during winter, when it is markedly damper there. You could try replacing the potting soil with fresh, if you find it to be mucky and dank smelling that would indicate it got too old. To check dig down to the bottom of the container. Fine particles move down through the soil column just like in the ground. An old potting mix in a tub can look acceptable on top and be quite unsuitable lower down.
