Driven from the comforts of society into the harsh wilderness, destitute outcasts reach the absolute peak of misery and starvation. Facing severe existential distress, these exiles are forced to scavenge for survival, gathering wild, uncultivated plants and roots that are normally unfit for human consumption. Their desperate search involves tearing and plucking whatever sparse vegetation they can find [מצודת ציון, אבן עזרא].
The primary approach among commentators is that they rely on a specific desert weed, eaten only under extreme duress. This plant is either associated with the salty earth in which it thrives [רמב״ן] or is simply identified as a fresh, moist herb [אבן עזרא]. Alternatively, rather than a single specific plant, they gather a random mixture of various wild weeds to eat [מלבי״ם]. To further quiet their relentless hunger, they strip the leaves off wild forest bushes and trees, consuming them just to stay alive [רש״י, מצודת דוד, אבן עזרא].
Their struggle extends beneath the surface as they dig into the earth to extract the roots of the desert broom tree. In the complete absence of normal food, these tough roots become their only meal [רלב״ג, תקות אנוש, רמב״ן]. However, a different perspective suggests these roots serve another basic human need. Lacking adequate shelter against the bitter cold of the desert, the outcasts use the roots as firewood to warm their freezing bodies rather than as food [רלב״ג, ביאור שטיינזלץ]. On a deeper, allegorical level, this bleak portrait of desert survival serves as a metaphor for the wicked and their ultimate punishment, with the tough root of the broom tree representing the harsh and prolonged judgment decreed upon them [אלשיך].