I too love learning about stuff from the art we trade here! For those of you who are with me on that, here's some trivia:
Traditionally in Brevens Bruk we/they use lily of the valley leaves for the wreaths for their maypole. They are in bloom in May here as well, and the flowers will be long gone before midsummer, but the leaves stay green! There's a process to the making of the wreaths that is difficult to explain in text, but basically you pick ~10,000 lily of the valley leaves, then you engage all your friends and family to have work stations where they 1) trim off the stems and throw away the ugly ones, 2) make 3-4 slits in the middle of each leaf (without breaking the edges), 3) fold it once over and once or twice sideways (it should look like a small bouquet) and give it to person 4, who) binds them to the wreath. That will take ~1 week. And on Midsummer's eve we decorate them with flowers and the two girls who bound each wreath carry them in a parade to the maypole, which is then raised. Here's a video where you can see what they look like (parade at 3:27):
View: https://www.youtube.com/watch?v=LDKa7Vy2Za4
Many people agree that Midsummer is the unofficial National Day of Sweden. (We do have an actual National Day on June 6th but nobody knows what to do with it...)