Just to add to Sabena’s post below, here are the snowdrops she mentioned.
And here is a Witch’s broom on a tree in the woods.
It’s a disease or deformity of a tree, where a dense mass of shoots grows from a single point. The causes are varied – infection, injury, parasites. See this Wikipedia article. Wikipedia adds that Witchs’ Brooms are of wide ecological importance. They generally tend to be inhabited by a wide variety of organisms apart from the causative organisms. Some of the invading organisms, such as some species of moths, are specific to particular types of witches’ brooms, relying on them for food and shelter for their larvae. Various larger animals may also nest in them.