User blog comment:Dryuuu/Why didn't Morgana tell Uther about Merlin poisoning her.../@comment-4879894-20120317114737

From the dialogues of 3.01, we understand that Morgana wanted only to neutralize Merlin, perhaps because she feared, above all, that Uther finds out about his magic and wants to execute her. After the Crystal Cave, since she's discovered the truth, it's more difficult to understand. But Morgana coudn't be sure that Arthur trusted her more than Merlin. If Morgana has told anything to his father, she coudn't be sure that Arthur, informed by Merlin, wouldn't interfere to convince Uther of the evil intentions of his sister. She didn't take the risk, then.