Q.indoor orange tree
I have a 20+-year-old orange tree (about 5′ tall) growing in a large plastic pot in my sun room. I have re-potted a few times over the years to accommodate the growth and wonder if it’s time again to do so. I am unable to find a larger pot, so it just keeps growing, needing frequent watering. I pinch off growth to maintain a topiary proportion, and wonder if this is preventing flowering. It has never flowered in all the years I’ve had it. How long do orange trees last? What should I do to ensure it stays healthy? I don’t need it to bear fruit, but flowers would be nice. I live in zone 5b, so I’m assuming it would never last outside in winter.

Certified GKH Gardening Expert
It can be difficult for indoor citrus trees to get enough light to flower, but some people have luck with this (this depends on the variety of tree as well). I also live in zone 5 and I bring my citrus outdoors during the summer and indoors during the winter to give them that extra light (but yours may be too big for this!) Pruning could also be an issue. See these articles for more information:
https://www.gardeningknowhow.com/edible/fruits/oranges/pruning-orange-trees.htm
http://homeorchard.ucanr.edu/The_Big_Picture/Pruning_&_Training/
http://www.extension.umn.edu/garden/yard-garden/houseplants/growing-citrus-indoors-in-minnesota/
https://www.gardeningknowhow.com/edible/fruits/citrus/growing-citrus-trees-indoors.htm