I have a Japanese Painted Fern potted in a container.
1. How can I help it survive winter in the pot without bringing indoors?
2. How can I best propagate the fern?
Thank you for contacting the Toronto Master Gardeners about your Japanese painted fern (Athyrium niponicum). A winter dormancy period is required for this plant, Without this, it will struggle and likely die. So it should not be brought indoors for the winter. The starting point for successful overwintering is the right pot. It should be large – more soil means better insulation for the roots. And it should be freeze-thaw resistant, so not ceramic or clay or cheap plastic, all of which will probably crack as a result of freeze-thaw cycles. These warmer-colder cycles will also kill the plant’s roots. The key to successful overwintering is keeping the soil temperature consistent. There are several ways to accomplish this :
- Sink the pot into the ground – the soil will provide insulation for the roots.
- Move the pot to an unheated garage or storage shed or corner of the garden, out of the sun, where it will be protected from the wind.
- Surround the pot with straw or autumn leaves to insulate the roots. Do not put anything on top of the fern – this could hold in moisture which could cause winter rot.
It is also important to provide some water to the plant each month or so, just enough to keep the roots from drying out.
Further reading on overwintering perennials :
How to overwinter perennials in pots – Garden Making
Japanese Painted Fern: A Hardy Perennial for Shady Gardens – Savvy Gardening
The easiest way to propagate Japanese painted fern is by division, in the early spring. The Toronto Master Gardeners Garden Guide on Dividing Perennials is a good source for information on how to do this. It is also possible to grow this plant from the spores which can be found on their fronds. This takes a long time (many months), and the resulting plants may or may not be identical to the parent. You can read about how to do this here.