Landscape hedges dying off

Question: Hi there! Thank you for taking this question - the evergreens along the front of our Rockville office have started dying off and I'm seeing webs strung amongst the brown and dying branches. Could this be some kind of mite creating these webs (and is that what is causing the die-off or are they merely opportunistic?) or is it biological like a deficiency in the soil? The curious thing is one side of the building is dying in almost a straight line while on the other side of the front doors we're seeing circular patches of dead leaves, also with the webs. I'm sorry I don't know what the hedge is - not my area of expertise. I'm more of a shade plant person in my home gardens. :) Any help you can provide is much appreciated!!

responder: Answered by the Home and Garden Information Center (HGIC), University of Maryland Extension. For timely gardening information and tips, subscribe to our Maryland Grows blog and quarterly newsletter. Follow us on Facebook, Instagram, and YouTube. Replied June 07, 2023, 3:29 PM EDT
response: Hi,  These plants are called Cherrylaurel and a commonly planted evergreen plant in Maryland both in home and commercial landscapes.  To your knowledge was an herbicide sprayed along the edge of the building? Maybe it burned the foliage. If not, it could just be constant heat and drought stress from their environment. They get reflective heat off of the brick of the building and assuming there is a sidewalk in front of the planting bed and parking lot beyond that so more heat island effect.  Whomever is doing the landscaping, it could be suggested that they prune out the dead foliage and add supplemental watering to help with drought  and heat conditions, especially right now. If you are able to water you would want to do so on a slow trickle of a hose, ideally early in the morning, and for a longer period of time to reach the root zone and thoroughly soak the ground. Then it would only need to be done about once a week.  The spider webs appear to be just from spiders finding opportunistic spots, and don't seem to be a concern.  From these photos we don't see any of the typical symptoms that cherrylaurel can get like shot hole fungus or scale issues. It could also be from a possible peach tree borer. You could look for frass shavings or sap oozing along the bottom of the stems. Cherry laurel are in the genus Prunus like ornamental flowering cherries and can get the same pests and diseases.  If you can practice some water saving tips going through your office, it would be beneficial right now, and always! https://extension.umd.edu/resource/conserve-water-your-landscape Potentially when the time is right, the office can replace the landscaping with plants that area better suited to a hot and dry environment.  Let us know if you have further questions.  Emily

responder: The Question Asker Replied June 07, 2023, 3:54 PM EDT
response: Hi Emily,Thanks very much for the detailed response! It does seem odd that one side would get a straight line die-off while the other hedge is experiencing circular patterns. I’m sure the company isn’t paying extra for herbicide spray so it’s a bit of a mystery.We can certainly increase watering during this awfully dry spring (I like the job Chuck Bell of NBC does in reminding people of how far off the normal precipitation pattern we are for 2023!) and we’ll ask our landscapers to do what you suggested - pruning out the dead areas. That will help us keep an eye on future affected sections in case it’s more than just drought & heat stress.Thanks again for the expertised - we appreciate the assistance!Kind Regards,Linda RobbinsOn Jun 7, 2023, at 3:29 PM, Ask Extension <<personal data hidden>> wrote:

responder: Answered by the Home and Garden Information Center (HGIC), University of Maryland Extension. For timely gardening information and tips, subscribe to our Maryland Grows blog and quarterly newsletter. Follow us on Facebook, Instagram, and YouTube. Replied June 07, 2023, 4:18 PM EDT
response: You're welcome! Let us know if you see other pests or disease symptoms on the interior that see off and feel free to send photos.