Of COURSE they need to be repotted! And root pruned, as well. You don't need a special potting medium for your citrus, just a very coarse textured, fast draining mix. If your local garden centers have a supply of orchid potting mix, that can work quite well. I'll also attach a link with my top choices for potting medium...they aren't sold at the retail level and you will have to ask a locally owned garden center or nursery to special order it for you. You are very correct in assuming that all of the litter dust isn't good for them. Not only does it coat the top surface of the foliage, which blocks out the already insufficient light, but it can clog the microscopic pores, called stomata or stomates, which are in the highest number on the lower surface. These pores are where plants exchange gases...CO2 and O2 in, then O2 and H2O out. If you can take some pictures of one of these plants so that we can see the size in relation to the container, as well as the general condition, we might be able to tell you if you need larger containers or if you can put them back into the same ones after a proper root pruning. The repotting/root pruning project can wait until spring. However, the plants would surely benefit from a thorough shower right now. Rinse the upper and lower surfaces of the leaves. You might want to do this when their potting mix is dry, so that a good drenching can be extra beneficial. Here is a link that might be useful: Fafard Heavy Weight Mixes

Citrus is host for the giant swallowtail. The cats of the giant swallowtail look like a gray/black/tan blob of bird poop, unlike the black swallowtail that is the pretty green/yellow/black cat. Giant swallowtails are also black, but they have the large yellow band runing from wingtip to wingtip across its back. I'm thinking of getting a myer's lemon just to get those gorgeous giant swallowtails spending more time in my yard. Black swallowtails like dill, fennel, parsley and a few others I don't remember.

I just wanted to post an update: The lemon tree seems to be in a stage of stasis. The leaves are not getting any greener, or yellower. I had started as Josh suggested on the 5ML dose. But that doesnt seem to be making any difference. I hated the nursery soil it came in. Last week, I decided what the heck and just repotted it into the gritty mix. I have repotted other plants before without any negative effects on the plants. So that gave me a bit of confidence. I barerooted the lemon tree. Rinsed up pretty much all of the previous soil mix. I didnt notice any roots coming off or getting damaged. So hopefully it will be okay. its been 5 days now since the repot. I guess this tree just wont react to anything I do to it. haha Still the same. Didnt get better, not getting worse. Certainly no leaf loss or yellowing. No new foilage either. Lastly, I decided to just remove all the lemons that had formed on it. There must have been 30 or more. Hopefully this will also help it. (okay I left one. The biggest one). =) I will update again in a while. This post was edited by TorontoNick on Tue, Jan 20, 15 at 23:14

It looks like a very nice healthy tree other than the leaves are missing. The twigs are green and therefore are producing food for the tree, I would not move it. You can use earth drill on a standard 110 drill and drill a couple of feed down about a foot away from the trunk and farther and fill these hole with compos and mulch around the tree out 4 foot radius to within 6 inches of the trunk. This should propagate and explosion of earth worms and they will do the digging for you. Meyer lemons need a lot of feed. about 1.5 times what other citrus need. Once the roots get established in the clay she should do fine. My guess to dry and very hungry. Water and feed an compost and mulch then give it some time.