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How to Grow Japanese Fern, a Colorful Fern

Caren White is a Master Gardener and instructor at Home Gardeners School. She has been associated with Rutgers Gardens for over a decade.

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I love ferns and grew a few different kinds until I moved to a townhouse with very little garden space. My favorite tall ferns were too large. Now I am growing the much smaller but more colorful Japanese painted ferns.

What are Japanese Painted Ferns?

Japanese painted ferns (Athyrium niponicum) are deciduous ferns that are native to eastern Asia. Here in the US, they are hardy in zones 3 – 8. They are reputed to be deer resistant. I can attest to that. The local deer do not eat mine. However, it is also claimed that rabbits do eat these ferns. There are not a lot of rabbits in my neighborhood but the ones that live here have not bothered my ferns.

Japanese painted ferns grow from rhizomes that spread slowly over time. The plants grow to 1 – 3 high and 1 – 2 feet wide, although most of the ones I’ve seen growing in gardens are on the smaller end of that scale. They are called painted ferns because the fronds are a silvery gray while the midrib (stem) is a burgundy color. There are different varieties that have slightly different colors including A. niponicum var. pictum which has a more red midrib. The pictum with the brightest red midrib is a cultivar called “Ursula’s Red”. The fronds on that one are more green than gray.

Japanese painted ferns do not reproduce from flowers and seeds. Those are recent developments in plant evolution. Ferns use the ancient method of spores. The spores develop on the backs of the fronds. They mature and are released during the summer.

The cultivar Ursula's Red.  Note its bright red midrib.

The cultivar Ursula's Red. Note its bright red midrib.

How to Grow Japanese Painted Ferns

Japanese painted ferns can grow in both full shade and partial shade. In full shade, their colors will be more muted. However, full shade is preferable in the southern portion of its range. They cannot tolerate the strong summer sun there, even in small quantities. In the cooler northern parts of its range, it should only get morning sun. Afternoon sun will scorch the fronds.

Some good places to grow your ferns would be a woodland garden, as an edging along a shady path or even on the banks of a shady stream or pond. They are a great way to add color to a shady spot.

Because they are smaller, you may want to plant them in groups for a larger impact. Space your ferns 12 inches apart. They will slowly grow together, over a period of years.

These ferns like moist well-drained acidic soil, pH 4.5 – 6.5. Although they like to grow in moist soil, they don’t like soggy soil which can cause root rot. A thick layer of mulch will help keep the soil moist in between waterings while also preventing weeds from growing which will compete with your ferns for moisture and nutrients.

A good way to tell if your ferns are getting enough water is to keep an eye on the fronds. If the tips start to turn brown, they are too dry and you should water more frequently. Aim to keep the soil evenly moist. Not too dry and not too wet.

Japanese painted ferns don’t need to be fertilized but if you want, you can apply a single feeding of a balanced fertilizer such as 10-10-10 in the spring.

In the fall, the fronds will die with the first frost. You can either remove them or leave them in your garden for winter interest. If you leave them over the winter, be sure to cut them down in the spring before the new fronds start to appear.

Japanese painted ferns plants along a shady walkway.

Japanese painted ferns plants along a shady walkway.

How to Divide Japanese Painted Ferns

Japanese painted ferns spread slowly so you don’t have to worry about them getting invasive or crowding out your other plants. Nevertheless, you may want to divide them every few years.

Spring, when the fronds are just emerging, is the best time to divide your ferns. Use a garden fork to dig up the clump of ferns. Then, using either pruners or a sharp knife, carefully cut the rhizomes apart. Discard any dead or diseased rhizomes. Make sure that each piece of rhizome has both roots and fronds. They will not grow without either one. Plant your divisions 12 inches apart.

© 2021 Caren White

Comments

Caren White (author) on January 29, 2021:

You're welcome! I love them.

Mona Sabalones Gonzalez from Philippines on January 28, 2021:

Japanese ferns are really beautiful. Thank you for this informative article and for the discovery of these lovely ferns.

Umesh Chandra Bhatt from Kharghar, Navi Mumbai, India on January 28, 2021:

Nice one. Thanks.