New laurel bushes dying
This looks to us like poor establishment. It does not look like a disease or pest problem. Laurels can be difficult to establish. They are shallow rooted and a bit finicky about soil conditions. They do not grow well in heavy (clay) or poorly drained sites and they like cool, moist, acidic soil.
When you installed the plants last fall, where they root bound in their pots? Did you loosen up the root ball and set the roots outward in the planting hole? Some plants start out tightly bound in their nursery pots and the roots fail to establish into the surrounding soil. They will survive for a year or so but then begin to fail if they aren't getting sufficient water/nutrients due to poor root establishment. You could pull up one of the symptomatic plants and check the root system. If it pulls up still in the shape of the original container, that is a problem. The roots should look white and fleshy rather than dark brown/black.
Newly established woody plants need regular watering in their first year to help the roots get established. Insufficient water or soil temperatures that are too high may have contributed to the problem. Mulch around the base of the plants can help to retain moisture and keep the root zone cool.
Here is additional information about shrub planting and post-planting care:
Thank you for this. They were installed by a professional landscaper, but we lost a lot of the bushes they planted so I suspect it’s poor work on their part. Soil is definitely clay, we are in water buffer zone. Should I dig up, amend soil and replant them all to be safe?
Yes, you could try replanting them, but we recommend that you wait until the fall to do so. The hot weather right now makes it a tough time for plant establishment.
Thank you so much for this - we will give the clethera more water and add mulch. Is there nothing I can do help the laurel over the summer ? I am resigned to losing one of them but Anything I can do to help them hang on until replanting?
so helpful, thank you!!
Keep the Laurel watered regularly during the summer. Check the soil moisture once each week and water deeply. A thin layer of mulch (no more than three inches deep and 3" away from the base of the plant) can help to keep the roots cool.