Asked August 15, 2016, 6:04 PM EDT
Multnomah County Oregon
Thanks for your question on transplanting and pruning hydrangeas.
To transplant, wait until the leaves have fallen off. The plant will be dormant by then. You may also wait until early spring (February-March), if your area gets freezing temperatures.
Dig up your hydrangea by driving a spade into the soil, all around the plant, at about the drip line (the width of the plant). Use a prying motion to loosen the roots from the soil. Go around several times, continuing to free the root ball. The root ball can be wrapped in burlap or a tarp to be moved.
Prepare your planting hole. It should be big enough for the root ball you are planting. The hole should only be deep enough so that the crown of the plant is at the same level it was in its previous home. Hydrangeas like a well-drained spot.
Water the plant well, after planting and add a layer of mulch (compost or bark) to protect the roots through winter.
Congratulations on getting so many blooms this year, but some pruning may be in order, if it hasn’t been done for a while. These tips are for the most common hydrangeas—mopheads and lacecaps. Other types will have different methods.
First, deadheading—not really pruning. After the blooms have dried and are no longer attractive, clip them off just above the first set of leaves below the bloom. This is where next year’s flowers will form, so you don’t want to cut them off.
True pruning. Hydrangeas don’t need much pruning. But, if the shrub has an abundance of shoots and the interior is crowded, thinning is helpful. Look for the older, woody stems or any dead ones. Take them out at the base. This will encourage new shoots to form, refreshing the plant. Do this in June or early July, before flower buds have been set for next year.