I have a narrow garden bed down the western side of the house, along a driveway. I would like some ideas on what to plant in this long 50cm wide space.
Narrow Garden Bed
Certified GKH Gardening Expert
Since you mention this is the west side of the house, the plants will receive either full shade or partial shade. If there is a convenient way to place a trellis or strings there, you could plant some vines that don't require full sun. Or you could plant herbs since many don't require full sun. There are also some flowers to consider.
Here are some ideas. Choose the smaller plants from the following articles and they should do fine.