Can you explain your interpretation of this sonnet?

I need a bit of assistance:

"Flowers I Would Bring"

Flowers I would bring if flowers could make thee fairer,

And music if the Muse were dear to thee,

(For loving these would make thee love the bearer);

But sweetest songs forget their melody,

And loveliest flowers would but conceal the wearer:

A rose I marked, and might have plucked; but she

Blushed as she bent, imploring me to spare her,

Nor spoil her beauty by such rivalry.

Alas! and with what gifts shall I pursue thee,

What offerings bring, what treasures lay before thee,

When earth with all her floral train doth woo thee,

And all old poets and old songs adore thee,

And love to thee is naught; from passionate mood

Secured by joy's complacent plenitude.