Im here in zone 5b of northern ohio. Purchased and planted 3 small ostrich ferns from Burpee in May, they were maybe 3" tall. I planted each in its own container (2 x 2 x 2.5 tall approx) in a medium of 1/3 potting soil, 1/3 organic compost, 1/3 perlite. Here it is end of July and they havent really grown at all. Upwards about 6" and outwards about 3/4 foot, although they are green and healthy. Keep in shade and moist at all times.

Are these suppose to be faster growers than this? What can I do to help them? ALSO.....should i bring them in for the winter or can I just keep them outside all winter?