I hope you will consider my answer. I am very new to citrus but have grown apple and peach trees. I had a similar problem with a dwarf red delicious apple tree a few years ago. We had put azaleas along the fence line where this tree was growing. After a few years the tree just seemed to 'droop'. DH decided to mulch under the tree and fertilize it a bit more than normal. No change. In fact the tree got worse. I did some reading on fruit trees and found that they do not like mulch and do not like other things growing near them. I pulled out all of the azaleas within a 6 foot area on both sides of the tree and removed all of the mulch. I then got a tiller and cultivated the ground added a heavy topping of Miracle Grow Potting MIX (hey it was cheap). I also put in 4 fruit tree spikes around the tree drip line. The next spring that tree made great blooms and pretty good fruit. The following year was even better. We do not live in the house anymore but that tree is still blooming and making apples - pretty good but the new owners are not pruning or fertilizing it properly.

I would say try to gently cultivate around the tree and add some rich top soil with citrus fertilizer. Sort of give the tree a 'tune-up'.

IMHO - do not know if what works for apples & peaches will work for citrus.

Good Luck,
DL

DL, thank you very much, I certainly will consider your advice. I have already removed all the plants that were planted near the drip line (did that months ago). Technically it is still winter here so I am not expecting a big growth surge just yet, but the signs of life up and down the branches keep us hopeful and the new leaves are noticeably larger.