Climbing hydrangea (cultivar anomala or petiolaris) shares many planting requirements with other hydrangea cultivars. But climbing hydrangeas have a few particular needs regarding siting in order to perform at their best. Careful attention to sunlight exposure, climbing support, soil quality and protection from certain weather conditions all support a healthy, long-lived flowering and climbing hydrangea shrub.
Choose a site for your climbing hydrangea that receives full sun or partial shade. The climbing hydrangea's foliage will tolerate deep, constant shade but bloom production will suffer. When growing in warm climates, the climbing hydrangea prefers afternoon shade in summer to prevent overheating, wilting and scorching.
Ensure that the planting location is protected from wind year-round. Petiolaris foliage and flowers can easily be damaged, torn or desiccated when winds occur regularly, placing the shrub under enormous stress and delimiting performance.
Site your climbing hydrangea immediately adjacent to a stable structure that can support the weight of the shrub as it climbs and has sufficient surface area to let the plant spread. A stable fence, a stucco or stone wall, a wooden garden shed or an old standing tree trunk are all good options because the plant's aerial roots can grasp onto them. Climbing hydrangea can climb up to 30 feet when unpruned, so choose a support location accordingly.
Plant the shrub in nutrient-rich soil with a high volume of organic material that is water-holding but still drains easily once saturated so water does not pool in the soil. Amend poor-quality soils such as fill soil with generous amounts of compost and aged manure when planting or as an annual topdressing over the soil surrounding the hydrangea's roots.
Water the plant so that the entire root mass and new surrounding soil is drenched with water. Maintain evenly moist, but not soaking wet, soil thereafter, never allowing more than the top 1/4 inch of soil to dry out between waterings.