This question came to us from a gardener in Queensland, Australia: "We have a mandarin tree that's about three years old now and doesn't seem to be growing and has never had any fruit. Our lemon tree has had one or two lemons but that's about it. If you have any ideas as to what we can try I would appreciate it."
We've never grown citrus, but did find these YouTube videos which might be a good starting place. The first is from Greg the Gardener with Lemon tree tips and the Kiwi Grower, who grows a variety of citrus trees including Mandarin.
But, we'd also like to pose this question to any of our viewers who have experience with citrus. If you have any tips or advice for our fellow gardener, please post in the comments below.