I have a Meyer lemon in a huge tub. I bought it last year and it was about 3 ft. high and full of blossoms. Over the winter in produced many lemons. None were much bigger than one and half to two inches in diameter. They mostly turned yellow by January, so have picked them randomly. Finally I picked the last of them about 2 weeks ago. (mid May) Now they are turning green again. What is with that?