Hi. I have a large laurel hedge that separates my neighbors property from my own. Last summer there was a spot that turned brown and the leaves died off. The bald spot appears to be spreading and the leaves don’t seem to be growing back. I was curious what could be causing it and if there is anything we can do.
Multnomah County Oregon
Thank you for your question. There are several pathogens, mostly fungal, that can create similar problems like this. Here are just two: https://pnwhandbooks.org/plantdisease/host-disease/kalmia-mountain-laurel-phytophthora-blight https://pnwhandbooks.org/plantdisease/host-disease/kalmia-mountain-laurel-root-rot Without examining the plant’s leaves and/or soil, a firm diagnosis is impossible. Are you able to take your photos and leaf and root samples to the county Extension office? Here are the 3 metro offices and their hours: https://extension.oregonstate.edu/mg/metro/have-gardening-question Good luck!
Thank you for your quick response. I am planning to take a sample into the office. Should I bring leaves from the area surrounding the bald spots? Also how much soil should I submit? Thank you again for your help with this!
You should bring leaves exhibiting any symptoms of problems. Each soil lab has requirements about soil sampling, and it is not done by the Extension offices themselves.. I suggest you use those indicated by this lab: http://www.al-labs-west.com/services.php?section=Soil%20Analysis
However, samples sent to them need to be referred directly. You might also ask them (for a bit more) to recommend amendments to the soil to assist your plants. Note that, if it is not a soil pH/nutrient issue, the Extension office may recommend you submit it to the OSU Plant Clinic, which can conduct studies on soil pathogens (bacteria, fungi and viruses, for example) which A & L does not study. Good luck!