The origins of the Latin name for this shrub are unclear. Some sources connect it with the Tambre river in northern Spain (which in classical times was known as Támaris, the 'great water'). Others suggest a link with Semitic languages, specifically via Hebrew tamar, 'palm tree'.

Though it seems extremely unlikely that tamarisk grew as far north as the Shire, it's implied that Sam recognised the plant (at least, it's described in a way that seems to suggest it fell within his considerable herb-lore). As a gardener, we'd expect Sam to have had a wide botanical knowledge, but it still seems slightly strange that a Hobbit who had never left the Shire should be familiar with a shrub from the arid southern lands. Perhaps tamarisk and other such plants had been brought northwards as exotic garden plants earlier in Middle-earth's history, and were still cultivated in parts of the north at the end of the Third Age.