The attached photo is of a Japanese holly I planted two years ago. The leaves...

Asked August 26, 2013, 9:32 PM EDT

The attached photo is of a Japanese holly I planted two years ago. The leaves turn yellow before completely drying out and falling off. I've been removing the branches that seem to be completely dead. Unfortunately, this has resulted in a barren looking plant. I give the plant a good soaking once a week. Could grubs be the cause of my barren looking holly? What intervention can I take to nurse this bush back to life? Thanks!

Montgomery County Maryland

1 Response

The problem appears to be a 'root' problem and that could be many things. We see no holes or disrupted mulch around the base of the plant which we would expect to see if the problem were voles. However, we do recommend that you rake away mulch from the base of the plant and not allow mulch to touch the base of this plant or any other woody plant in your landscape. In this case, rake away enough mulch from one side of the shrub to gently dig around the roots and examine their condition. By the way, if it is vole damage, you could simply tug on the shrub and see if it is loose in the soil. If the roots are blackened and limp, it could be a 'root rot' caused either by disease or excessive soil moisture.
We are unable to determine if the mulch is wood mulch or shredded rubber mulch. If it is the latter, the problem could be zinc toxicity. If so, remove the mulch and replace with wood mulch. Also, we cannot determine the depth of the mulch, but the shrub could be planted too deeply or covered with excessive mulch. Either situation would result in suffocation of the roots.
Once you have examined the roots, if they are still light colored, firm, and fleshy, be sure to limit the mulch depth, continue to water the shrub when needed and you could provide a small amount of a nitrogen fertilizer.
Please respond if we have overlooked something of if there is more information that could be helpful.