Let's just keep on blaming the weather for lots of things. We'll use it to explain the phenomenal spread of some perennials that run underground, from last fall to this spring.
There was no frost in the ground all winter in our neck of the woods and it sure looks to us as if that constituted a field day for many plants that spread by underground rhizomes: Solomon's seal (Polygonatum species), queen of the prairie (Filipendula rubra), and groundcovers like Canada anemone (A. canadensis). Sure, they are spreaders in any circumstance but this year some hit a new high. Ditto, some woody sucker-producers, such as Japanese angelica tree, Aralia elata, which is popping up 12-15 feet from the main trunk, 2x the norm.