we have a lemon bush that has a lot of long limbs going straight up
We have a lemon bush that has a lot of really long limbs that go straight up. None of these limbs have lemons on them. The lemons all are on the lower part of the bush. Are these long limbs suckers and should they be pruned off? This is the first year that our bush is giving us lemons; the bush is about 3 yrs old.
To identify suckers, find out where they are coming from. If they arise from the roots, the base of the tree, or anywhere below the graft union, they would be suckers from the root stock, and should be cleanly cut as close to the tree as possible. https://www.gardeningknowhow.com/ornamental/trees/tgen/tree-sucker-removal-and-tree-sucker-control.htm
If the branches are emerging from the tree above the graft union, or from any of the side branches, they are branches from the tree. A sign that your tree is healthy, growing roots, and sending out new branches. Your tree is still very young - meet it's cultural requirements, and it should soon start fruiting. https://www.gardeningknowhow.com/edible/fruits/lemons/lemon-tree-not-fruiting.htm