The ere bright buds are now shadowy pits
and doze in muddy beds a quite brief sleep...

The tone in those two lines reminded me of a lullaby. The lyric subject, as @firststeps has said, points to the "imagery of motherhood" and seems to sing its evolving circle in a lullaby to the Bassil's sprouts "before they come to be the slender ladies/ which are to mourn her own silvery babies". Really beautiful indeed, gives you a mother-daugther bonding feeling. <3