Q: What kind of flowers are great friends?
A: Rose buds!

Explanation: Roses are one of the best known flowers.  As a rose grows, in the spring you will notice buds.  Rose buds are little bumps on the stem of a rose from which the flowers will appear.  Yes, roses are beautiful! (Be careful of the thorns, though.)

Friends are, well, you know what friends are.  There are many synonyms for the word friend.  One of those synonyms is bud, short for buddy.  Your bud is your pal, is your friend, is your bestie, is your bff.  You get the idea.

This joke is funny because it plays with the word bud: a baby flower and a friend.

If you would like to see a rose bloom from a bud to a flower, watch this: