Dear Lynne:

Thank you for contacting the UVM Extension Master Gardener Helpline about you red osier dogwood (“ROD”) plants. You state that you planted them in the spring of 2022 with compost and Pro-Gro. Were the three RODs about the same size when you planted them?

Thanks for the pictures. It looks like the plants are in a sunny location surrounding a wellhead and have been mulched with wood mulch. In the first photo, I assume the least vigorous plant (ROD#1) is in the foreground on the left; the more robust plant (ROD#3) is closer to the driveway and, in the picture, it's to the left of the wellhead; and the “middle range affected” (ROD#2) plant is on the right in the foreground. Although ROD#1’s two major stems look sickly, there is healthy looking new growth at the base of the plant. The same is true for ROD#2.

Although RODs can tolerate a wide range of soils, they prefer rich, well-drained soil that has consistent moisture and is slightly acidic, with a pH between 5.5 to 6.5 (although the factsheet from the University of Minnesota (link below) advises a soil pH of 6.1 to 8.5). I doubt that soil pH is the issue since the three RODs are in close proximity, in soil with the same pH and nutrients (but have different levels of vitality).

When you planted the RODs, did you use compost and Pro-Gro to amend the existing soil or to replace it? If the latter, too much compost drains quickly, and plants can dry out. The attached link provides further information about using compost (RODs generally need little to no supplemental fertilizer). Again, since three plants are in the same location and were planted with the same medium, it is unlikely that the soil is the issue.

https://extension.umn.edu/nutrient-management-specialty-crops/correct-too-much-compost-and-manure#:~:text=While%20adding%20compost%20to%20your,your%20plants%20and%20the%20environment.

While the soil pH and nutrients may not be the issue, location might be. It looks like the RODs are planted on a small mound where ROD#1 sits at the highest level and ROD#3 is at the base of the mound. The soil at the top of the mound probably drains more quickly so ROD#1 may not have as much moisture available to it as ROD#3 gets at the lower edge of the mound. Take care to make sure that ROD#1 gets sufficient water. I recommend that you weed out the large dandelions and other weeds that surround ROD#1 and ROD#2 so that the RODs don’t have to compete with the weeds for moisture and room to grow.

Additionally, the smallest ROD shows evidence of browse, which has stressed the plant. I suggest that you surround the two smallest plants with a cylinder of chicken wire staked in the ground or plastic mesh fencing to protect the plants until they are bigger and more established. Prune out the dead wood on the plants.

There is a chance that the least vigorous plant suffers from a disease called Botryosphaeria canker, but I cannot tell from the pictures. I attach a link to a factsheet about this disease to help you investigate this possibility and how to manage it.

https://ag.umass.edu/landscape/fact-sheets/botryosphaeria-canker

I think I see some spots on the leaves of ROD#1 and ROD#2. This may be caused by a common fungal disease called Septoria leaf spot. While it may be unsightly, it usually does not kill the shrub. The link below provides further information about this disease.

https://yardandgarden.extension.iastate.edu/faq/leaves-my-red-twigged-dogwoods-are-spotted-and-beginning-fall-why#:~:text=The%20spotting%20and%20premature%20leaf,Heavily%20infected%20leaves%20drop%20prematurely.

You can find further resources about RODs in the links attached below.

https://extension.umn.edu/trees-and-shrubs/redosier-dogwood

https://www.missouribotanicalgarden.org/PlantFinder/PlantFinderDetails.aspx?taxonid=279363&isprofile=1&basic=red%20osier%20dogwood

https://plants.ces.ncsu.edu/plants/cornus-sericea/

https://plants.usda.gov/DocumentLibrary/plantguide/pdf/pg_cose16.pdf

We hope that this information is helpful. If you have additional questions, please let us know.

Good luck.

Pat