The youngest flower buds, pickled, are delicious peppery capers. It may need to overwinter indoors a year or two to produce the lovely 3" white flowers with whiskery lavender centers. Meanwhile, the vigorous bush needs such severe pruning that we can eat shoots and leaves.
The buds, plus the immature leaves and tender shoots, have been enjoyed in the Mediterranean for 2,500 years. Yummy on pizza and bruschetta. The flowers only last one day, but, where the plant is happy, it blooms profusely from May to early fall. Dried caper leaves can be used as a vegetarian substitute for rennet in making cheese. Find out more about growing caper bush and eating caper plants.
Here's a plant that will be far outside its comfort zone in most gardens. What this scrambling, prickly little shrub wants is discomfort: inhospitable, stony soil, desert-dry weather, intense sunlight, and temps over 100°F. Give it all-day sun, as little water as possible, and super-sharp drainage with sandy, rocky soil or potting soil for succulents in a container.