Viburnum Mariesii looks sick
I am attaching 3 photos of my 15 year old viburnum mariesii that suddenly looks like it is on its way out. I had it pruned by a reputable landscaper 2 Years ago. I cannot recall what it looked like last year - the first season post pruning - but this year it looks awful. There are bare patches on limbs with no leaves and where there are leaves i cannot see any buds. I am most attached to this viburnum and hope you can suggest what to do. Thanks. Julia
Montgomery County Maryland
You may be dealing with several issues. Viburnums grow best in at least 6 hours of sun and the site looks shady. They do not tolerate heavy clay soils with poor drainage. The last several seasons we had a lot of moisture. Soils were saturated due to heavy rains and this reduces oxygen in the soil and affects the root system. We also had a drought last summer and this affects the roots too.
Also, Viburnums can be susceptible to a canker disease called Botryosphaeria
which can cause branch dieback. This can be prevalent on sites due to site problems or environmental issues like drought. There is no chemical control and all you can do is prune back to healthy wood. See more https://extension.umd.edu/hgic/topics/cankers-trees-and-shrubs
At this point, all you can is make sure the soil drains well and water during dry periods. Mulch should be no thicker than several inches and keep away from the base of the trunk. We recommend that you prune dead and any crossing branches. Prune no more than 1/3 of the shrub to try and stimulate new growth. If there are overhanging tree branches, perhaps you can prune them to let in more sunlight.
Here are links for more information on viburnum https://web.extension.illinois.edu/hortanswers/plantdetail.cfm?PlantID=464&PlantTypeID=8
Thank you for this information and strategies to combat - now that i look closely there are definitely Botryospheria cankers present. I have tried to trim to healthy growth and will mulch and water as needed. Thanks again. Julia