S. R. Faruqi:

baaliidah = with the head raised; proud

The affinity of 'grass' with baaliidah (meaning 'grown up') and nihaal (meaning 'tree') is very fine. The sarcastic theme of the verse, and the style of its expression-- in which is a mood like the taunt of a homey person [ghareluu sha;x.s]-- are interesting. The difference is only that the style of speaking is that of a homey person, but he's expressed the idea in poetry.

The image of burnt grass growing from the grave or the dust of those killed by love is fine in itself, and how excellent is the construction ulfat-kushto;N as well! It's a pity that later people have declared eloquent expressions like this to be unacceptable [matruuk].

The sky is indeed lofty after all, so to say that it goes along nose in the air, head up, as though it had graciously made happy those slain by love, is a good 'cause' [ta((liil]. The wordplay of 'burnt' and 'dust, ashes' should also be noticed.

FWP:

SETS
MOTIFS
NAMES
TERMS == AFFINITY; 'ELEGANCE IN ASSIGNING A CAUSE'

No doubt the idea is that the dust/ashes of slain lovers would be so completely ruined and sterile that even the smallest sign of life from them would be remarkable But why would the heavenly sphere [sipihr] be 'proud' of this achievement, and carry its head high or its nose in the air? The heavenly sphere isn't usually very nurturing toward those that live beneath it; it's much more likely to send down a balaa than a benefit. The wordplay of baaliidah seems to be the main source of energy in the verse.