Japanese painted fern is a lot different from the plain green ferns that many gardeners are most familiar with, such as the interrupted fern (Osmunda claytoniana). True to its name, Japanese painted fern is more colorful, offering triangular, silvery leaves (called "fronds," technically) that sport an arching habit. As if that were not exciting enough, they also have grayish-green in them, as well as purplish midribs, making them variegated ferns. The fern is a slow-growing plant that adds about 12 inches to its overall size each year.
|Common Name||Japanese painted fern|
|Botanical Name||Athyrium niponicum|
|Mature Size||About 18 in. tall and wide|
|Sun Exposure||Partial, shade|
|Soil Type||Moist but well-drained|
|Soil pH||Neutral, acidic, alkaline|
|Hardiness Zones||3, 4, 5, 6, 7, 8|
Japanese Painted Fern Care
Japanese painted fern is one of the easiest plants to grow. It tolerates very acidic soil and deep shade, two conditions most plants are not very fond of. There are two key elements to remember when growing Japanese painted ferns:
- You must protect the colorful fronds for which this foliage plant is grown from exposure to the hot afternoon sun. Such exposure will burn them.
- Work amendments into the soil before planting to feed your Japanese painted fern and help get it established.
Japanese painted ferns spread via rhizomes and may even naturalize over time. Happily, for the gardener who demands low-maintenance plants, this spreading occurs very gradually. But the spreading nature of the plants does allow you to divide them (spring is best) and multiply the number of them available for use elsewhere in your landscaping.
While Japanese painted fern is listed as being a plant for partial shade or full shade, the decision is often made for you based on where you live. At the more southerly end of its range, Japanese painted fern should be grown in full shade. Northerners have more choice in the matter. Still, the fact that the plant achieves its best color in the north if grown in partial shade more or less makes the decision on plant location for you.
An essential requirement in growing Japanese painted fern is soil with excellent drainage. Otherwise, the plant may suffer from root rot and fungal diseases.
Keep the soil evenly moist (but not soggy). Otherwise, browning on the fronds will occur during the heat of summer.
Temperature and Humidity
The Japanese painted fern does best in moderate temperatures of 55 to 80 degrees Fahrenheit. It also prefers a moderate humidity level of 40 to 60 percent.
As long as you work organic soil amendments into its soil occasionally (including feedings of manure tea), additional fertilization should not be necessary. But if you prefer commercial fertilizers, apply a balanced fertilizer in spring, carefully following the instructions on the label.
Types of Japanese Painted Ferns
There are numerous types of Japanese painted ferns, including:
- "Wildwood Twist": As the name suggests, the fronds have a twisted appearance. This plant is a silvery gray color.
- "Burgundy Lace": this plant has deep burgundy stems; the unique color is repeated in striations on the fronds.
- "Pictum": This plant has an attractive combination of silver and red colors throughout the fronds.
Pruning is not necessary to help the plant grow. Trimming away dead or diseased fronds is a good choice throughout the growing season. Feel free to prune the fern to keep a desired shape.
Propagating Japanese Painted Ferns
Japanese painted ferns spread slowly through rhizomes. Propagating them through division is easy. During the spring, dig up the ferns carefully and pull the roots apart. A mature plant can easily be divided into 3 or 4 sections. Plant those sections immediately where you want them to grow, and water them thoroughly. They should take well to their new area within a few weeks.
How to Grow Japanese Painted Ferns From Seed
Japanese painted ferns don't set seed; they travel by spores. Therefore, the best way to add Japanese painted ferns to your landscape is through division.
Japanese painted fern is a deciduous plant, so the fronds will die back in the winter. This is normal, and the fern should return with a robust fullness in the spring.
Common Pests and Plant Diseases
Fortunately, Japanese painted ferns don't have many pests to fight. Snails or slugs might nibble on the fronds. If they show up, remove them with your hands, then treat the fronds with neem oil. To prevent further pests, create a barrier around your plants with mulch or rocks. Rabbits are more of a problem, as they do love to eat the fronds. Deer, however, aren't usually an issue.
If the fern is in too-moist soil, it can show signs of fungal issues or root rot. Avoid this by ensuring that the soil is well-draining.
Common Problems With Japanese Painted Fern
Even when grown in an area sheltered from bright sunlight, Japanese painted ferns lose some color once spring yields to summer (the fronds become greener). It is also natural for some fronds to brown up and die over time; cut off such dead fronds when you see them, for aesthetic purposes. Browning can also be the result of a lack of water; to help keep the soil from drying out, apply a mulch around the plants.
What plants are similar to Japanese painted fern?
How long can Japanese painted ferns live?
A well-tended Japanese painted fern can live for five to six years. Keep in mind that this plant is easy to divide, so the original plant can live on in offspring for many additional years.