I have 2 established Japanese Painted ferns in a part-shade garden.....Ursula's Red & Burgundy Lace. One is huge, the other is only half its size this year. I don't see any reason why it isn't seeming to catch up....usually they are both about the same size. They are planted about 2-3 feet apart. What can I do to help the little one catch up (or what would be a reason for the difference in size?) They have been in the garden for at least 4 years now.

Thanks!

:0) Phyl