I have two patches of columbine in a light woodsy area. One is red, candensis, and the other is blue, a variety of blues. These are established plants, and have bloomed for years, but this year not a bloom in either patch. No insect damage that I can see. Plants look healthy. I have other columbine in various places, though not as many plants, yellow in the perennial garden, purple in another spot, and mixed colors, and they bloomed. The age of the problem plants is varied, as they re-seed plentifully. Any idea what happened to them?

TIA
LAS