Hydrangeas are popular garden shrubs, cherished for their large, striking blooms. Gardeners sometimes move these mature plants because they have outgrown their space, receive too much shade, or require relocation. Moving a large shrub is challenging, but proper timing and technique ensure the hydrangea can successfully transition to its new home.
Identifying the Best Window for Transplanting
The best time to move a hydrangea is when the plant is dormant. During dormancy, the shrub is not actively producing leaves or flowers. This allows it to direct resources toward root establishment in the new location. This period occurs after the leaves have dropped in the fall and before new buds begin to swell in the early spring.
Many gardeners prefer late fall, ideally four to six weeks before the ground freezes solid. Transplanting then allows the roots to begin growing and settling into the soil while it remains warm, preparing the plant for the following spring. Early spring is also suitable, provided the move happens before the plant breaks dormancy. Moving a hydrangea during summer heat or when it is fully leafed out should be avoided, as this increases the risk of transplant shock due to moisture loss.
Essential Steps for a Successful Move
Preparation begins at the new site, where the planting hole should be excavated first to minimize the time the hydrangea is out of the ground. The new hole must be dug two to three times the diameter of the shrub’s root ball. It should be dug only as deep as the root ball is tall, ensuring the hydrangea sits at the same level as its original spot.
Next, prepare the shrub for digging by pruning back some top growth to reduce overall size and potential moisture loss after the move. For mature plants, estimate the root ball size based on the stem diameter. The root ball is often 10 to 12 inches wide for every one inch of stem diameter measured six inches above the ground. Hydrangeas have a fibrous, shallow root system, so aim for a wide, rather than deep, root ball.
To begin excavation, use a sharp spade to cut a perimeter circle into the soil outside the estimated root ball size. This clean cut severs the feeder roots and prepares the main root mass for lifting. Carefully work around the plant, gradually loosening the soil beneath the root ball while keeping the root mass intact. Placing the heavy root ball onto a tarp or burlap aids in lifting and transporting the shrub to its new location.
Immediate Care After Relocation
Once the hydrangea is positioned in the new hole at the correct depth, water it thoroughly and deeply. This initial soak settles the backfill soil around the roots and eliminates air pockets that could cause the roots to dry out. Water the plant in stages, allowing the water to drain, and then adding more soil and water as needed until the hole is completely filled.
Applying an organic mulch layer, such as shredded bark or leaves, helps conserve soil moisture and maintain a consistent soil temperature. Spread the mulch two to three inches deep over the root zone. Keep the mulch several inches away from the main stem or crown of the plant to prevent rot. If the move was performed when the plant was not fully dormant, reducing the foliage can lessen the demand for water from the newly disturbed roots.
Avoid applying fertilizer during the first year after the move. Fertilizer encourages the plant to grow new leaves and stems instead of focusing on root development. The primary focus for the first growing season is keeping the soil consistently moist, which supports the establishment of a strong new root system. Consistent water is the best tool for helping the hydrangea overcome relocation stress.