The explanation of "Description of Spring" [added above] is that it is a love sonnet of unrequited love summed up in the rhyming couplet of lines 13 and 14:
And thus I see among these pleasant things
Each care decays, and yet my sorrow springs !
The message is that all things are renewed in spring except for the love of his lost beloved.
Surrey, Henry Howard, earl of Surrey, lists things in nature that throw off winter's oppression and embrace spring's renewal. Some of these are the buck (deer) and adder (snake), the flower and bee, the nightingale and the hills. He ends by saying that his beloved has not cast off the oppression of winter nor embraced renewal of spring: she still does not like him and still rejects him.
Surrey experimented with Petrachan sonnet form. The structure of this sonnet is 14 lines comprised of one opening quatrain followed by a octet and concluded with a rhyming couplet. The volta is line five. To restate this, the first four lines form a quatrain devoted to the topic of the coming of spring: "The soote season, that bud and bloom forth brings". The next eight lines form an octet devoted to the topic of nature's summer changes: "Summer is come, ... / The hart hath hung his old head [antlers] ...." The switch from the first topic to the second occurs at line 5; the switch is called the volta or the "turn." The rhyme scheme is a consistent abab / abababab with an aa couplet.
There are two things to note. The first is that spring in England can be very damp and cold, thus events that some of us from warmer climes associate with spring are delayed until summer itself, for example, "The buck in brake his winter coat he slings ;". The second is that, although Surrey was a contemporary of Shakespeare, Spenser and Sidney, Surrey borrows a gentler form of Chaucer's much earlier Middle English, thus many words need defining as their meanings are obscured. Luminarium.com provides a very useful gloss of these words.
1 [soote] Sweet.
2 [eke] Also.
3 [turtle] turtledove.
4 [make] Mate.
5 [spray] Sprig; spray of flowers.
6 [hart] Deer.
7 [head on the pale] last year's antlers [discarded].
8 [pale] Fencepost; picket.
9 [brake] Bracken; thicket.
10 [flete] Fleet; fast.
11 [smale] Small.
12 [mings] mixes.
13 [worn] Worn out; over.
14 [bale] Bane; destruction.
15 [care] Worry; worrisome thing. (Anniina Jokinen)