I have several citrus that I have moderate results with. After watching the February video about coplanting, I'm thinking they are lonely. What underplanting would be good for my little trees? They vary is ages 12 years down to 6 years old (that does not relate to their sizes lol) I have Meyer lemon, a lime and a mandarin, they are in roughly 12-18 inch pots as they are still pretty small.