“What am I supposed to do with my potted hydrangea in the winter? It’s too big to move around. I did cover it with leaves and pine needles. It lost all its leaves. Is that normal?” Question from Kriss of Steilacoom, Washington.
Answer: Most hydrangeas are deciduous, which means they drop their leaves in winter. Potted specimens are most often big leaf hydrangeas (Hydrangea macrophylla), particularly in the mild regions of the Pacific Northwest. They display big clusters of showy blue, pink, or white blossoms in summer and have large, robust green leaves. There are many cultivated varieties of these hydrangeas that vary in hardiness, most withstand winters in USDA Zones 6b to 9, so they should be well protected in your USDA Hardiness Zone 8 or Sunset Zone 5 location. In areas with colder winters, they can survive but typically die to the ground and don’t reliably flower. This is because they typically bloom on the previous year’s wood.
It sounds like you are doing the right thing. Protect your container specimen through the winter with protective cover, like leaves, straw, and needles. When the leaves start to appear on the stems in the spring, remove the cover, and keep a lookout for any stem dieback. If there are any dead stems, cut them off to keep your specimen looking nice. If you want to shape the shrub for good looks, wait to prune further until it has finished blooming. (Click here for a full tutorial on how to prune hydrangeas).
Otherwise, keep your shrub watered, fertilized, and replenish old mix with a quality outdoor potting mix, such as Black Gold® Moisture Supreme Container Mix. These shrubs grow best in full sun to partial shade.
Happy hydrangea growing!
Black Gold Horticulturist