Teucrium canadense in the Fern Valley Prairie

I worked in Fern Valley for 4+ years, and I don't remember ever seeing this plant. There are several hundred square feet of it flowering now. I looked it up in BGBase and it was planted just about 15 years ago; I guess it's been biding its time. The thing is, biological systems are complex. The ecology of a grassland is beyond my comprehension. I do know that variations in weather from year to year and season to season can allow for sudden explosions in populations and corresponding sudden drops. Last year Bidens filled the Meadow and Prairie, having gone from a very minor player to what almost appeared to be a monoculture. I see Bidens now but at nowhere near last year's levels. It seems to me that Helianthus mollis has gone from being a quite large percentage of the Prairie to one of any number of plants. You can't take anything for granted, every year there'll be something different.

Everything I read about Canadian (American) Germander suggests that it likes moist habitats. Apparently the same superabundance of rain that has made this such a wonderful year for Hydrangeas has tipped the scales to the point a hydrophil can dominate what's usually a dryish environment.