TAMARISK. The word “tamarisk” does not occur in the Bible in the KJV, but is found in the Moffatt and Goodspeed translations, where the word “shrubs” in Genesis 21:15 and “tree” in 1 Samuel 22:6 and 31:13 is tr. as “tamarisk” or “tamarisk tree.” Tamarisk would certainly be quite suitable as these shrubs would grow in droughty regions. This is prob. the reason why Abraham made his grove of tamarisks in Beersheba (Gen 21:33).
Tamarisks have tiny, scale-like leaves which hardly transpire at all; thus, they are suited for hot, dry places. They grow well in sandy soils, and so would grow in the Shur Desert, where Hagar wandered (21:9-17), and it was in the shade of the tamarisk tree (prob. Tamarisk aphylla) that she laid her boy Ishmael.
International Standard Bible Encyclopedia (1915)
(1) ’eshel (Ge 21:33, the "grove," margin "tree"; 1Sa 22:6, the King James Version "tree," margin "grove"; 1Sa 31:13, the King James Version "tree"). The (British and American) translation is due to the similarity of ’eshel to the Arabic ’athl, "the tamarisk."
(2) ar`ar (Jer 17:6 margin (compare Jer 48:6), of the Bible "heath" (which see)).
The tamarisk (Tamarix, with various species in Palestine, chiefly T. Syriaca) is a very characteristic tree of Palestine, especially in the Maritime Plain, near the sea itself, and in the Jordan Valley. Eight species are described. They are characterized by their brittle, feathery branches and by their tiny scale-like leaves. Some varieties flourish not infrequently in salty soil unsuited to any ordinary vegetation.
E. W. G. Masteran