We've had these two for 2 or 3 years, they both always came back except this year. One of them isn't showing any signs of life, while the other just popped back up. Should I give it more time, or pluck it?

Update: On closer look, I do see some growth on it, so I will give it more time.

After living in Colorado (usda2b) for 22 yrs, columbine are hardy plants, it's is Colorado state flower. The only ones I noted that would not come up regularly were a wild form whose flower stem grew only 3" tall, and had a 1" very pretty blue flower (nearly as blue as the "Suggest a Change" that's above the messages box. The normal garden type that I grew had tap roots going 6" deep and survived inches to feet of snow, and 2 nights a year of -18 degrees F. They had no mulch, just sandy soil, and never fertilized.

When I think about it, that particular plant was always slower than the other one for some reason.

Update: I'm fairly certain it's a gonner. No signs of life other than weeds growing around it. The other one is doing well.