Climbing Hydrangea

(Question)

I have a climbing hydrangea that I would like to plant next to my garage in the hopes that it will grow along the stuccoed wall. It’s currently tied (abut doesn’t appear to have attacked itself) to a small wooden trellis. I am was hoping you might be able to tell me how close/ far it should be planted from the wall and if I should remove it from the trellis (that came with it when it was purchased last fall). Your expertise and suggestions are much appreciated! Thank you, ~Meredith

(Answer)

Thank you for contacting Toronto Master Gardeners.

Climbing hydrangea is a lovely flowering vine that can reach 30 to 40 feet.  It clings by “twining” and with aerial roots along its stems.  The vine is best planted in rich, fertile soil that is moist, but well-drained.  Climbing hydrangea prefers part to full shade.  It can be quite slow to establish and doesn’t always bloom for the first few years after planting, but once it is established it is vigourous.

Once the vine becomes large it can get heavy so it is important to have a sturdy structure for it to climb on.  It is likely best to secure a well-constructed trellis against your garage that will be able to hold the weight of the vine as it matures.  If you allow it to climb directly on the wall there is a chance that it will damage the stucco or grow into areas where you don’t want it.  Once established, climbing hydrangea can be pruned to control its size.  Pruning should take place after the vine has flowered. Any overly long growth can be pruned back at the same time.

When planting against a wall, allow a gap of 1 – 1 ½ feet between the wall and the plant. Prepare a hole that is as deep as the rootball and about 2-3 times wider.  Remove the trellis that came in the pot, firm the plant into the hole, fill with the soil that was dug out and firm gently with your hands and water well.  Mulch around the plant with organic material to improve water retention being careful to keep the mulch away from the stem of the plant. Plants along a wall may be in a rain shadow so monitor and water when dry especially in the summer.

April 27, 2021