Concise Bible Dictionary:

Common Juniper
These words are supposed to refer to the Arabic Arar, which is a juniper (the Juniperus sabina). It grows on the rocks even to their summits in most sterile soil. It stands therefore as a fit emblem of the man who “maketh flesh his arm, and whose heart departeth from the Lord” (Jer. 17:66For he shall be like the heath in the desert, and shall not see when good cometh; but shall inhabit the parched places in the wilderness, in a salt land and not inhabited. (Jeremiah 17:6)). Moab also, under the judgment of God, is compared to “the heath in the wilderness” (Jer. 48:66Flee, save your lives, and be like the heath in the wilderness. (Jeremiah 48:6)). The juniperus communis is another species.
Juniperus Communis
Juniperus Sabina