for why > because
3 Nor guidance of herself in her did dwell. 4 But the aged nurse, her calling to her bower,
bower > room
5 Had gathered rue, and savin, and the flower
rue > (Ruta graveolens, a bitter evergreen shrub, a symbol of sorrow and repentance, called the "herb of grace" after the God- given grace that follows true repentance. It was used in the middle ages as a defence against magic; and was prescribed for a nervous heart, menstrual problems, etc. Rue was specifically not to be taken by pregnant women) savin > (Junipera sabina, a small evergreen shrub, the dried tops of which are abortifacient; cf. 207.52:5)
6 Of camphor, and calamint, and dill,
camphor > (The camphor tree, Cinnamomum camphora, which yields a powerful and volatile oil used in many herbal preparations) calamint > (Calamintha spp., aromatic herbs of the thyme family, used, like the closely related mints, for nervousness, insomnia, etc.) dill > (Anetha graveolens, a herb of the parsley family, also used as a calming agent)
7 All which she in an earthen pot did pour, 8 And to the brim with colt wood did it fill,
colt wood > (Not in OED. Two explanations seem possible: (1) green wood ("colt" being an adj. meaning young, immature); or (2) the tough roots of coltsfoot, Tussilago farfara, a herb of the dandelion family)
9 And many drops of milk and blood through it did spill.