From the title, we can tell that the speaker is addressing this poem to a group of virgins. He's telling them that they should gather their "rosebuds" while they can, because time is quickly passing. He drives home this point with some images from nature, including flowers dying and the sun setting. He thinks that one's youth is the best time in life, and the years after that aren't so great. The speaker finishes off the poem by encouraging these young virgins to make good use of their time by getting married, before they're past their prime and lose the chance.