2. proud-pied: brilliantly multi-colored.   trim: finery.

4. that: so that.   heavy: melancholy; morose. —The planet Saturn was associated with gloom and sluggishness.

5. yet nor: yet neither.  lays: songs.

6. different flowers: various flowers; variegated flowers.

7. summer's story: pleasant narrative.

11-12. They were but sweet, but figures of delight, / Drawn after you, you pattern of all those: They were only sweet, only delightful forms, produced in imitation of you, the model of all sweetness and delight.

13. and, you away: i.e., because you were absent.

14. shadow: portrait.   these: the flowers.