Caper, << KAY puhr, >> is a pickled flower bud used as a seasoning in salads and in sauces, including tartar sauce. The buds come from a low, trailing shrub called the caper bush that grows primarily in the Mediterranean countries. The caper bush blooms early in summer and has pinkish-white flowers with four petals. The unopened buds are pickled in salt and vinegar to make the seasoning.