Leaves turned yellow, then brown on edges.   Dark brown spots and holes have popped up on some

Question: Can you tell me what’s happening to about twenty of my forty bushes this winter?  See attached picture

responder: Answered by theHome 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 March 16, 2023, 12:57 PM EDT
response: From a distance it is clear that the plants are stressed but it is difficult to say why.  The spotting is a common disease called 'shothole', but it doesn't look terribly concerning.  We can't see signs of a scale pest that can bother them, but become aware of it and keep an eye out:  https://www.missouribotanicalgarden.org/PlantFinder/PlantFinderDetails.aspx?taxonid=252685&isprofile=1&basic=cherry%20laurel The yellowing looks more concerning and makes us suspect a root issue. When did it begin and do you notice any pattern to which ones are yellowing?  Is the soil drainage o.k.? These plants like moist but well-drained soil and will not stand for wet roots.  Were they planted within the last couple of years, and how were they cared for/watered afterward? When planted, were they rootbound, or was a burlap cover left on? (Even some potted ones can have a burlap sheath and sometimes what looks like burlap can have plastic netting embedded in it.)  We can't tell what variety you have there but cherry laurel can get pretty large. While even the compact, dwarf cultivars like  'Otto Luyken' grow to only 3-4 feet tall, they can tend to grow as wide as 6-8 feet and yours look a good deal closer than 3 feet apart.  Here is a page from Missouri Botanical Garden on Cherry Laurel:  https://www.missouribotanicalgarden.org/PlantFinder/PlantFinderDetails.aspx?taxonid=252685&isprofile=1&basic=cherry%20laurel   Christine

responder: The Question Asker Replied March 16, 2023, 3:09 PM EDT
response: Thank you.  These were planted in Fall 2020 — don’t know if they were planted in their burlap sacks.   The discoloring happened in winter and more on their south facing sides.  Of sixty bushes, forty have turned yellow and brown over the last three/four months.I believe the soil is not good, as we’re in DC and the builder likely just used what was on the site.     Thank you so much for your help.    Ed

responder: The Question Asker Replied March 16, 2023, 3:09 PM EDT
response: Thank you.  These were planted in Fall 2020 — don’t know if they were planted in their burlap sacks.   The discoloring happened in winter and more on their south facing sides.  Of sixty bushes, forty have turned yellow and brown over the last three/four months.I believe the soil is not good, as we’re in DC and the builder likely just used what was on the site.     Thank you so much for your help.    Ed

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 March 16, 2023, 4:01 PM EDT
response: Hello Ed,  We agree the condition of the soil might be playing a role here, especially if it was compacted from construction or foot traffic and/or drains poorly during wet weather or irrigation. While Cherrylaurel as a group are fairly adaptable to a variety of conditions, they can become winterburned (dried leaf edges or pale, brittle foliage from drastic swings in temperature during winter) and might be stressed if in full sun with minimal irrigation during dry summer or autumn periods. (Depending on how closely they were monitored for watering during the first year or two of establishment, this also could have had an impact on how well they rooted-out.) We've seen a variety of evergreens develop winterburn damage this year, probably due to the one or more periods of mild spells followed by a rapid chilling, especially if there were breezes, sunny weather, and low ambient humidity at the time (all of which combine to strip leaves of moisture they can't replace quickly enough). If the stems are unscathed or at least the roots healthy, winterburned plants can recover well once they resume new growth; the older, damaged leaves will be shed, either in spring or later.  By itself, the extensive leaf yellowing suggests a nutrient problem in the foliage, but not necessarily a nutrient deficiency in the soil itself. It's often instead an issue with roots not being healthy enough to absorb the nutrients they need, no matter how plentiful they may be in the soil. (This is why fertilization is generally not recommended unless other factors like root rot can be ruled-out.)  You can probe round the crown (where stems emerge from the soil) and just below the soil line to see if any burlap wrapping and twine ties remain on the root ball. If they were container-grown and not burlapped when sold, hopefully the installer loosened the roots if they were tangled prior to planting. If not, that can significantly hamper establishment. Burlap that isn't treated to resist decay will eventually rot away so the roots can grow unhindered, but how long this takes is hard to predict. While checking the crown, you can also see if any plants have vole damage, which would appear as gnawed-off bark either just above or just below the soil line.  You can also inspect the thicker, lower parts of the branches for signs of White Prunicola Scale, which is the insect pest Christine was referring to. We find them with some regularity on Cherrylaurel, especially stressed plants. The scale would probably have to be fairly prolific to cause this much widespread plant stress, so it's not likely this is a factor (or at least not the most serious one), though in that instance they would at least be easy to spot given the white coating over their bodies.  The shot hole is a very common disease of Cherrylaurel and doesn't need treatment (nor are fungicides very effective at preventing its return), but it seems to be a disease more common at nurseries than in home landscapes because of the routine overhead watering from sprinklers that wets the foliage. If you irrigate these during summer or autumn, do so in a way that minimizes foliage wetness by either watering in the morning or only wetting the soil surface. Only water when the soil a few inches down into the root zone is becoming somewhat dry to the touch. Once root rot sets in from prolonged soil saturation, it isn't treatable and may not be something from which the plants can recover.  It might not hurt to have a laboratory soil test performed for this part of the garden. While this can't diagnose diseases or confirm the degree of soil compaction, it might illuminate a particular nutrient level or acidity level (pH) that needs adjusting to reduce the stress on the plants. You don't need to necessarily follow any fertilization recommendations the lab may automatically send back with the results and can also ask us for help interpreting the results if needed.  Going forward, regarding soil quality concerns for either these plants or any replacements, you can amend the soil with organic matter (compost, typically) to help reduce compaction, improve drainage plus water-holding capacity during drought, and generally improve conditions for beneficial soil microbe growth that helps plant roots absorb what they need. For in-ground plants, amending soil can be done by layering atop the soil about an inch of compost yearly (perhaps under a layer of about two inches of mulch, which also adds organic matter as it decays). For new plants, an amendment can be mixed into the soil dug out of the hole before it's back-filled. Don't enrich the soil too generously or this can backfire a bit and interfere with moisture levels around the roots, but enough compost to give the soil a somewhat crumbly texture (instead of, say, pottery clay) is a good goal. You'd have to experiment to see how much is needed to add since it will depend on what you're starting with; there's no set recipe to follow.  For now, this is just a waiting game if none of the above ailments appears to be a factor. See if the plants produce new growth that looks normal later this spring, and don't be too alarmed if a number of older leaves fall off around the same time. If little or no new growth is evident by late spring, there might be too much root decline (from whichever cause, or possibly overlapping causes) to salvage them. In the event that happens, we recommend replacing the plants with a mix of species so the planting as a whole will be more resilient and less prone to reacting badly to the same conditions in the future (such as a pest outbreak, weather abnormalities, diseases, etc.). Since the mature size of Skip Laurel (also called 'Schipkaensis', the variety these appear to be) is potentially 8 feet high and 6 feet wide or so, you may be able to get away with many fewer plants if some wind-up needing removal. Therefore, you might not need to replace them all in the event some die out.  Feel free to send us additional photos if new symptoms appear, if you're uncertain about the symptoms from one of the above sources of damage, or if you would like confirmation new growth looks good later this spring.  Miri

responder: The Question Asker Replied March 16, 2023, 5:22 PM EDT
response: Thank you so much for this detailed review of the problem and possible solutions.    Ed

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 March 16, 2023, 5:26 PM EDT
response: You're welcome.