Were can I order a Citrus plant or tree?

Check around your area for local nurserys as these are your best bet. You can talk to a specialist to find out exactly what you need to do in your area to care for the citrus trees. There are some reputable nurserys which do business online, but there are many more who won't sell you a quality product.

I have not personally dealt with online growers & shippers before, so the best I could give you would be to research the company well before purchasing.

om thinking about order from michiganbulb

I answered your post in the grapefruit forum on this matter.