https://www.nhm.ac.uk/discover/the-henna-plant-transcending-time-religion-and-culture.html

Here is a great article about the Henna plant, which has been used for thousands of years for various uses. ”Night of the henna’ is a widely practiced event where a bride’s hands and feet are adorned with intricate mehndi patterns to celebrate her wedding day’. I myself like the long history of painting skin with henna and painting of mummies. “One of the earliest uses of henna can be dated back to Ancient Egypt, where henna paste was used to stain mummies and mummy wrappings. The Egyptians believed henna retained a person’s spirituality. The lawsone also made the skin stronger and resistant to decay. Some mummies have been unearthed with flaming red hair that was dyed with henna, probably at the time of embalmment.”

Why Henna is quite a common name in Finland, I don’t know. Could be wordplay with Hanna or henna plant travelling here and my mother liked the color.