How To Grow A Hydrangea Tree (Hydrangea Paniculata): All You Need To Know

Potted and Repotted Tree Hydrangeas If you have a container-grown hydrangea, it may need to be repotted every two years. Here's what you need to know: Repot your hydrangea in spring or winter. Choose a slightly larger container with good drainage. Use a mix of compost and a hydrangea-specific fertilizer as the growing medium. Cover the roots and stems with soil and place the container in a shaded area for a few days before gradually exposing it to more sunlight.