Hi
To have them growing for 14 years is impressive.

I lost my original 4 in the winter of 2011 even though insulated it got down to minus 10 where I live for a solid 6 days , but I remedied that by buying 1 foot logs and grafted them into the top of the old stumps and low and behold they rooted well.
I think the secret is to keep the logs wet during the summer months and not letting them dry out too often, also I mulch heavily with bark each Autumn which also helps protect the roots which are clearly visible.
I also spray the foliage and the logs with a liquid seaweed feed every second week during the summer and the leaves really green up and just look so much healthier .

Hope that helps a little

Gg

Thank you Gg for your comments.

I also feed the ferns with seaweed food every 2 weeks and keep them well watered so not sure why they are not doing so well. They get wrapped within an inch of their life during winter, it gets very cold and windy where I live.

Snowwhite