The diminutive primrose

I picked up a few perennial primrose plants last year and planted them in a partly shady corner near our car-port. It produced some nice flowers but then it appeared to whither away prematurely. I thought it was due to the pesky chipmunks that have drilled giant mine-shafts all over the place and near their roots. What chance does a frail plant have against such aggression?

The primroses proved me wrong. I did not even notice the buds forming, yet they are suddenly in bloom!