Malört is the name of the herb wormwood in Swedish.
The swedish name means "clothing moth herb", and has been used to fight cloth moths among other uses. Also especially popular spirit flavoring, which it's latin name hints of.
Artemisia absinthium
Artemisia absinthium
In our family it's generally been a tradition to go out in the night of August 24th each year to pick some wormwood, and then infuse some plain alcohol with it to have for the coming months. We generally don't leave it in as long recipes call for though, 24h instead of multiple days so the taste is a bit milder.
Like many old traditions the reasons have for many become lost to time, and now it's an accepted fact that that's the magical night to get some wormwood.