I have a silver leaf dogwood in a container for many years over 8 that has done well for me. This year sporadic leafing this is current picture I did fertilize with 15-3-3 because I thought is was over due BUT it may have been a mistake. is it just slowly leafing I see I few more leaves today but still worried :) its my baby along with my Japanese maple :)
Thank you for contacting the Toronto Master Gardeners concerning your potted dogwood tree
Congratulations on keeping your containerized dogwood healthy for 8 years. There are a number of questions that need to be answered before I can make any recommendations. When was the last time the shrub was repotted? Have you added fresh soil to the container? What type of soil are you using?
Dogwood trees/shrubs have very fast-growing root system and as a result the shrub can become pot bound very easily. It could be that the roots are pot bound and there is not enough soil in the pot to provide nutrients to the roots, which will result in a reduction in leaf output. You can correct this by removing the plant from the container and inspecting the roots. Do you see circling roots? Circling roots will become girdling roots and the plant will eventually die from lack of air, water and nutrients. If the root ball is small enough, gently pull the root ball apart. Loosen and untangle the roots and then spread them apart. You can then place the plant into a container one size larger with fresh soil.
If the root ball is too large to loosen the roots you may want to cut off the outer layer of circling roots with a clean sharp knife. This will stimulate new roots to grow. “Box Cutting “ Containerized Root Systems by the University of Minnesota gives step by step instructions on this technique.
The soil you choose for your container is equally important. Container soil should retain adequate moisture while at the same time provide adequate drainage. Never use the soil directly from your garden for a container grown plant.
Make sure to place the plant in its new container at the same height as it was previously. Use your fingers to gently push the soil around the roots making sure that all roots are in contact with the soil. Slowly water the shrub to reduce large air pockets and make sure to water until you see water draining out of the pot. Make sure that the pot has adequate drainage and that the shrub does not sit in water.
Lastly, look at the shrub and prune out any damaged, dead or crossing over branches at the base. The University of Tennessee has an excellent article on The Art of Growing Dogwoods in Containers
Here’s to many years of enjoyment of your silver leaf Dogwood!
May 7, 2021