Container citrus: lot's fruit, not many leaves
 

I have some container citrus about 2 years old - lemon, lime, citron,
limequat - that have tons of fruit and continue to flower but not many
leaves. They are kept well watered and fertilized and in full sun at least 8
hours day. I live in southern zone 8. Any suggestions to force more leaf
flush? Thanks for any help. -Scotti