I live in estate, Ontario. I have 2 trees, one is a mini one started from seed. The mini is 21 years old and did not get fruit for 17 years till I got the second. Within 6 Mon. It got flowers, then fruit. I assumed it needed the other to pollinate. Last winter I almost lost both when they became root bound. I repotted them and put them outside and cut back the dead branches. The mini came back immediately but the other just now has started to go. It also has a flower on it. Do they not have a male and female as I originally thought?
Lemon trees do not need cross-pollination to set fruit. Lemon tree flowers have both male and female sex organ, so self-pollinate. Your tree requires both sun and warm temperatures in order to set fruit. As well, as it spends most of the year indoors, it requires hand-pollination to replace what the bees would provide if it were outdoors. Here is a link to an earlier posting to the Toronto Master Gardeners website that discusses strategies for pollination as well as other “musts” for caring for your tree: Lemon tree care