I am thinking of planting against my house wall but the soil isn't that deep (approx. 150mm) due to house foundations/rubble which I guess is typical for that…
They are fully to frost hardy and will prefer sun or semi-shade with fertile, moist but well-drained soil. They will require more shade in dry areas; provide shelter from cold, drying winds. Some hydrangeas become chloritic in shallow chalk soil.
You can propagate by softwood cuttings in the summer.
Pests, diseases or disorders
Watch out for powdery mildew, leaf spot, honey fungus and aphids, scale insects and red spider mites.