This is taken from the book Southern Herb Growing by Madalene Hill and Gwen Barclay, 1992.
Madalene Hill was the founder of Hilltop Herb farm which now is retreat and resturant. 

Salad Burnet, Poterium sanguisorba
    An evergreen growing 12 to 18 inches high when flowering, salad burnet is easily grown from seed.  Happiest in full sun, this delightful plant is tidy in its hummock-like growth and is at its best in a deep South winter.  The dark green leaves impart a delicate cucumber flavor to the winter salad.  In hot weather the leaves become tough and taste of watermelon.  It is a good plant for both border and accent.
    A common name for burnet in Germany is pimpernel, and in France pimprenelle.  While it has a strange, small button-like flower with pale red, fringy petals, it scarcely qualifies for it's other common name, "scarlet pimpernel."  Great burnet (Sanguisorba major or S. officinalis) does qualify, with its tall, burgundy, berrylike blossoms.  Found growing in botanical gardens of eastern Europe and Russia, it is a spectacular plant with large leaves and 3-5 foot bloom stalks.
    Salad burnet was formerly classified as Sanguisorba minor from the Latin sanguis (blood) and sorbere (to stop).  It has a styptic quality, and the plant was used long ago to staunch the flow of blood.  Its new assignment to the genus Poterium (Greek- poterion- drinking cup) relates to its early use in beverages. 
      The color of burnet's small flowers is more intense on the side that gets the most sun (south or south east) - hence it was call a compass plant.  It grows wild over most of Europe.
    As with borage, the cucumber flavor is derived from the oils in the leaves of burnet.  The plant tastes like cucumber in the cool fall and spring months.  In the dead of winter, it remains evergreen but does not have much flavor, and the leaves are inclined to be tough.
    To use burnet leaves in a salad, simply cut a handful of small leaves from the center, and chop or cut them into salad greens.  Burnet grows from a crown, and new growth after shearing is very rapid.
    An excellent vinegar can be made with leaves for salads and dressing, giving a hint of cucumber flavor.  Cover the leaves and tender stems with a good quality white wine or cider vinegar, and let stand in a dark space for several weeks.

    Use burnet with asparagus, celery, beans and mushrooms.  It is great in potato salad and can be used generously in soups. 

Used with permission. From Southern Herb Growing by Madelene Hill and Gwen Barclay (Shearer Publishing).