As mentioned before, trolls seems to have this urge of stealing children, especially the royal children and then preferably daughters. Another interesting aspect is that the trolls also seem to have a need to place these maidens in the soil, with only the head above. One can look at it as a gruesome image of today where some cultures bury people up to the neck and then stone them to death as a collective punishment.
Or one can have a comedic standpoint, what expects troll by planting people? Do they think that they will take root like a potato?
I will take with the opening of folktale that has this motif.
The castle of stars
There was once a queen who was out sailing in a ship. Unexpected the silent water turned into a steep sea and all on board the ship thought that now was their last hour coming. It could not get worse, but it did. A large merman, a troll of the ocean grabbed hold of the ship. The troll promised that it would bring the ship safely to harbor if the Queen promised to give him what she wore under her dress. The Queen knew no better than that she had to promise. The troll would have the child she was carrying when it was 12 years old, but she had to guard it well so it was never baptized or learned to read. With grief the queen agreed on this. The vessel was brought ashore, but the Queen’s grief was no less when she told the king what had happened.
When it was time the queen gave birth to a beautiful son. She did not want to know of him and they put him away to a poor family that had plenty of children. There he grew up, but he was treated like a changeling. As he got older, he wanted to learn to read like other children, but they claimed he was too stupid for this. Instead, he was put to herd the kings cattle. The animals had to herd whatever weather, though he begged to be excused when the weather was too bad, well he was not. He made himself a simple cottage on the moors where he could stay warm. The other shepherds who were older than the boy took pity on him and taught him to read. When they went to confirmations they baptized him and gave him a book that he always carried with him.
When the boy was 12, the king came and wondered if the boy would like to sail in a boat. The boy had never been more happy. The king came to him and moreover he had never seen a boat let alone been in one. The boy followed the king down to the beach where he saw a boat. The boat had no sails or oars. The boy jumped into the boat and the king pushed the boat out onto sea , turned and did not look back , eventhough the boy cried and asked him to come and save him . The boat sailed quickly out on the sea. The boy wiped his tears, took out the book that he always carried with him and began to read. It started to burn in the boat, but the boy continued to read . Large ships came sailing and sailors shouted that he had to get away or they would sail over him . The boy heeded it not, the only thing he did was to read. It was so cold that the boy thought he was going to freeze to death , yet he did not stop but continued to read. Out of the sea rose as a bad troll with fiery flame of fire out of his nose and a nasty huge gap. The troll swallowed him and the boat . Then the boy fell asleep .
And when the boy fell asleep he was just a boy when he woke up he was a young man. And the boat was standing on some nice grass on a nice beach. The boy stepped out of the boat, he let the book be in the boat and and as far as I know it is still there.
The young man went on a big , broad way. He was quite surprised when he neither saw nor heard a single living being. When he got longer, he was startled when he heard a young woman’s voice : «Do not step on my head.» He looked down at his feet and saw the head of a young woman. The rest of her body was underground. “Can I help you,” said the boy. “No, you’re too young for it takes a lot to save me,” said the maiden . “I have tried something before I,” said boy , “I rescued me from a seatroll and I try whether it be with trolls or giants.” “You are big in words and I will try you in action,” thought the princess, because that is what she was. “I am buried in the soil by three horrendous giants that has slain the king, my father and they have bewitched the country. Half a mile from here is the castle where I was born. It shines like gold and is called the castle of stars. During the day, the giants stays in their own rock castle, but at night they are the castle of stars and looking to see if people are coming. Dare you to be in the castle three evenings in a row and endure the punishment, then I am free. You shall be king and if you want I will be your bride.”