We have two citrus trees, a Meyer Lemon and a Mandarin Orange. Unfortunately, we do not live where citrus are reliably winter hardy, so they spend the winter inside.
Citrus bloom in the winter. In our case, citrus bloom inside, in the winter, where there is a lack of natural pollinators. This year we're helping things along with a soft brush. Hopefully we're end up with more fruit than we did last year.
Last year we got one fruit from each plant, so our odds look pretty good.