Climate extremes can negatively affect plant fitness, but the implications for mixed-mating species are unclear for two reasons: 1) mixed breeding may give flexibility that buffers change, and 2) climate change co-occurs with other factors (invasion, pollinator declines, and site conditions) that may overwhelm or exacerbate climate effects. I experimentally increased temperature in the late spring prior to the peak in flower production, to test the effects of an abrupt warming event on plant growth, reproductive dynamics, pollinator limitation, and the response of the surrounding plant community which is composed mostly of aggressive exotic grasses. The rare violet demonstrated weak positive responses to the climatic perturbation, by growing significantly larger and producing more CL fruit. There was no detectable change in the invasive grass species. This boost favouring the rare violet could play an important role in its persistence by allowing it to increase its growth and reproductive success under certain climatic conditions.