Cherry Laurel issues

Question: Hello!
We planted 6 Cherry Laurels at my office on April 24th. I watered them daily for the first two weeks and have watered about every other day since then. Now many of the leaves are brown and are falling off and dying but the shrubs do have new growth. The soil does have quite a bit of clay in it and we are wondering if that's the issue? If so, what can we do to help the shrubs? Thank you!

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 09, 2023, 3:54 PM EDT
response: The symptoms on the cherrylaurel appears to be mostly scorch, which is abiotic (meaning not due to a pest or disease), but there appears to be a small amount of Cherry Shot Hole as well, a very common leaf infection among cherrylaurel and cherry trees. The latter isn't easily treated (prevented, technically, as existing infections can't be cured) and would involve several applications each year of a fungicide, which we usually do not recommend. Fortunately, other than some cosmetic damage, this disease seldom does serious damage to cherrylaurel and can largely be ignored. It will also probably be less obvious as plants mature and fill in. Avoid wetting the foliage when they need water since wet leaf surfaces are more vulnerable to infection, especially if watered late in the day where leaves remain wet overnight.  The scorch is probably due to transplanting stress combined with watering frequency. It's hard to say how often they'd need water but both over- and under-watering can cause root stress and leaf damage as a result. The best way to judge when watering is needed is to feel the soil about six inches deep. If it's becoming somewhat dry to the touch at that depth, water thoroughly; if damp instead when checked, watering can probably wait.  Complicating the impacts of watering can be how well (or not) the root ball was prepared prior to planting and how deeply plants were installed. Cherrylaurel can be sold potted or burlapped. If potted, tangled or matted roots should be loosened before planting; if burlapped, remove the burlap (tangled roots can be addressed if present but often they're not) and any ties holding it in place, putting the root ball "naked" into the ground. For potted plants, the type of potting mix used inside the root ball holds water very differently than the surrounding soil, so it can help to try to remove at least some of it and to use only native or minimally-amended soil from the planting hole to fill the voids back in when planting. This helps ensure that the core of the root ball both doesn't stay too wet after watering or get too dry between waterings since the surrounding soil type would be draining differently. Sometimes the soil immediately around a root ball is sufficiently moist but the mix within the root ball has gotten dry, making it harder to tell when to water and how much to water without over-saturating the surrounding soil.  Having said all that, cherrylaurels are pretty adaptable plants and as long as they're not very dry or always soggy they will probably come through okay. The rest of its foliage is a nice dark green color, which suggests it's not being grossly over- or under-watered as that often causes the foliage to pale or get a sickly yellow-green color before falling off or browning. For now, just continue to monitor its watering needs, which should not be as often as it was being watered before as that sounds a bit high. Don't apply any fertilizer, and if bothersome (or if it helps you monitor for worsening symptoms), you can clip off some of the individual leaves with the most amount of "burn." While they might not continue to produce new foliage throughout summer (many trees and shrubs are finished with new branch growth by midsummer), they should at least continue growing roots so they are more well-established by next year.  Miri

responder: The Question Asker Replied June 13, 2023, 11:46 AM EDT
response: Thank you so much for your quick reply - that was EXTREMELY helpful! I truly appreciate your help. So, it looks like our cherry laurels will be ok…fingers crossed!    Have a wonderful day!     Sincerely,    Kari

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 13, 2023, 11:57 AM EDT
response: You're welcome!

responder: The Question Asker Replied July 06, 2023, 1:36 PM EDT
response: Good afternoon,     Here’s an update – I really thought we were in the clear with our Cherry Laurels but they are not looking good now. They did have some really great green growth going but not it seems like that is going brown. We have been checking to see if the bushes are dry before watering so as to not overwater them but I don’t know what to do now.                         The picture below is one of the bushes from the other bed. These three bushes look pretty good? I’m still not sure if it’s the clay that it’s in the soil? What kind of soil do they grow best in and what don’t they like?         Thank you for your help!     Sincerely,     Kari

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 July 07, 2023, 11:19 AM EDT
response: Hello Kari,  Unfortunately the plants with mostly-brown foliage are probably too weakened to recover well (or quickly) so should be replaced. It looks like the scorch has worsened (as opposed to another problem arising) and it's hard to tell exactly why, though it's certainly possible too much root damage had already been done by the time the symptoms had first appeared. Evergreens sometimes frustratingly take a while to manifest damage since their waxier foliage is slower to lose moisture than that of deciduous plants. The root ball top showing in the first photo suggests the roots are still very tangled so it can be difficult to get enough moisture down into that dense root mass (with its very well-drained potting mix in its core) that isn't soaked-up by any surrounding garden soil, especially clay. Clay is excellent at retaining water but it can be harder to re-wet if it were to get very dry, and it is also prone to compaction if stepped-on too much which keeps it from draining excess moisture well enough to keep roots healthy. Either extreme can cause foliage scorch because roots that aren't functioning well or which stay too wet (and can't "breathe") can't provide the foliage with what it needs to stay healthy.  This condition is not treatable so any scorched leaves can be removed from plants you wish to keep, and time will tell if the shrubs are able to pull through and regrow. It might take a while if they have to regrow some roots before replacing foliage, especially since not a lot of shrubs produce much new foliage growth during the second half of summer since they need to start internal tissue preparations for winter already. Since some of the plants are more badly scorched, we were recommending their removal instead since that much leaf damage suggests that any dormant buds for foliage growth on those branches may also be too damaged by lack of moisture to leaf-out later.  Adding a bit of compost in with clay upon planting, if it's compacted, can help alleviate that a bit, though there can also be an advantage of not amending soil and just working with what you have so the roots don't have to get accustomed to varying soil types as they grow out of their root ball. This only works well, though, when that old soil in the root ball is removed as much as possible upon planting; something not easy to do if the plant happens to be very root-bound, which is not uncommon for cherrylaurel by the age they are sold. Otherwise, if amending with compost, aim for a mixture that is crumblier than the straight clay but not so loose that it can't be formed into a "snowball" of soil, which may be too crumbly. Do not use sand or stones at the bottom of the planting hole to improve drainage, as this actually can backfire and worsen drainage.  Cherrylaurel are fairly resilient plants overall when it comes to soil conditions as long as they're not super wet or dry, but it's not uncommon for new plantings of most shrubs to struggle a bit if they are having trouble growing roots outside of their original root ball. Continue monitoring for watering needs for the remaining plants, and if you want to try again with replacements of those too burnt to keep, you should be able to plant now (or any time between now and early autumn) as long as they too can be regularly monitored for water.  Miri