This poem is the romantic wooing of a passionate shepherd in his efforts to convince a young woman to come join him. This line of the poem is the shepherd's description of the kinds of clothes the young woman would be able to wear. The straw would be woven in some attractive way and the ivy buds would be added to make it all the more becoming. Interestingly though, ivy buds would wither away if they were picked and woven into a belt. The shepherd then tells her that her clothes would have coral clasps and amber studs. Both of these materials would be very expensive and very rare -- and most importantly well beyond the financial reach of a lowly shepherd. Coral comes from the oceans, and not the oceans near England. Amber is a semi-precious stone. They would be very beautiful and tempting, but the description is hardly realistic. The passionate shepherd is making suggestions about how wonderful life would be if she were with him, but none of the things he has to say are very viable. The work of shepherd is boring and hard. Shepherds were kind of at the bottom of the social strata of society in this time period. He suggests that life will be wonderful, but it would have been quite the opposite.
The imagery contained in this poem emphasizes its status as an example of the pastoral tradition. The pastoral in literature is a genre that romanticizes a rural, rustic lifestyle, which is portrayed as exemplifying the best that life has to offer: the beauty of nature, the wholesomeness of living outdoors, and the pleasures of making a living off the land via farming or animal husbandry. We see the pastoral reflected in poetry from this period, and also through various characters in Shakespeare (like the shepherds Salvias and Phebe in As You Like It).
Of course, this would be a hard sell for a man trying to convince a fine lady to be his wife. The poem is written in the voice of the shepherd, who tries his best to convince his lady that her life will be filled with fine and beautiful things. At first, the descriptions are of objects found within the immediate surroundings: beds of roses, a cap of flowers, and wool pulled from the lambs to make her gown. These are all materials at the shepherd's disposal, and are plausible supplies for the gifts he promises. There then seems to be hint of fantasy and embellishment, because the following stanzas promise the lady things made from silver and gold, and these are mixed in with the natural objects. We see this in the line mentioned: the straw and ivy buds are the natural objects easy to procure, while coral and amber are substances not necessarily found close by or obtained without expense. This line shows the shepherd is willing to make promises he may not be able to keep, and yet like the rest of the poem, it hints at his hope for riches and comfort to help keep his future wife happy. The romantic imagery of the pastoral is maintained throughout the poem.