Plant Profile: Arachniodes (Spider Ferns, Bristle Ferns)

Plant Profile: Arachniodes (Spider Ferns, Bristle Ferns)

It may be an oldie but it's a goodie

By and Published December 13, 2022

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Arachniodes (Spider Ferns, Bristle Ferns)

It’s hard to look at an Arachniodes and think…well, there’s another typical fern. We became fascinated with the genus after growing the yellow variegated Arachniodes simplicior ‘Variegata’ as a house plant. We had no idea at the time that it would be winter hardy, nor did we have any understanding of the immense diversity to be found within this genus. Arachniodes are generally easy to grow in typical woodland garden conditions under standard garden soil conditions.

Plants in the genus Arachniodes (around 78 species) are primarily evergreen ferns from Asia, whose fronds are covered with a thick, waxy sheen that makes many of them look almost plastic. The name Arachniodes is derived from the Greek arachnion which means spider’s web, due to the intricacy of the small pinae that compose each frond. This genus is commonly misspelled Arachinodes, Arachnioides, or Arachnoides. Many people pronounce it incorrectly as A-rach-knee-oy-dees as it just seems more natural and there are so many other plants that are oides — this one is an odes! You can remember it like this: “it may be an ode but it’s a goody.”

Arachniodes aristata (Prickly Shield Fern) Here is another wonderful garden plant that is almost unknown outside fern-nut circles. This species is found over a very wide range (Japan and Korea south to Australia). It has fairly thick fronds but not as fake plastic in texture as A. simplicior, so if that one reminds you too much of Decoration Day, perhaps this fern is for you. Plants are easy to cultivate in general woodland conditions and slowly spread from slender rhizomes. We grow two wonderful selections of this wide-ranging species. (Hardiness Zone 6a-9b, at least)

Arachniodes aristata ‘Ali Shan’ Our plants are grown from wild-collected spore from our 2008 trip to Taiwan, where it was found on Ali Shan growing in Cryptomeria and bamboo forests. This plant displays dark green very thick leaves, like thin plastic, and fronds that are held fairly upright with a slight arch. The 1-2.5’ long fronds are very wide in outline and create a dramatic effect as a specimen plant.

Arachniodes aristata ‘Okoze’ (Okoze Dward Prickly Shield Fern) Arachniodes ‘Okoze’ is a super rare, highlyminiature, rock-garden sized selection. Our 15-year old patch is only 3” tall, and has spread to make a 1’ wide patch. The dark green plastic-like foliage looks and feels like an artificial plant created for miniature train enthusiasts. Although evergreen in most winters, Arachniodes ‘Okoze’ can become deciduous at temperatures near 0 degrees F. Be sure to plant this gem where it won’t get overtaken by more aggressive plants in the woodland garden.

Arachniodes coniifolia (Hemlock-leaved Bristle Fern) An amazing evergreen bristle fern with highly divided leaves with a somewhat triangular frond. Fronds are arching and reach 3-4” length but extend upward only 1.5-2’ due to the arching nature. We received this plant as Arachniodes sp. “Chile” from Judith Jones. We finally narrowed it down to a species (from China rather than Chile) in 2022. It hails from southern China, Bhutan, Nepal, and Myanmar where it can be found at middle to upper elevations (to at least 10,000’) growing in moist forests among bamboo and even into subalpine habitats. This is a fantastic plant for adding year-round fine-textured foliage to any woodland garden. We are working on production of this species so hold on, it’s not commercially available yet. (Hardiness Zone 6a-8b, guessing)

Arachniodes davalliaeformis (Shiny Bristle Fern) This fern hails from one of the Japanese islands where it forms a slowly spreading clump of 2’ long, arching, evergreen, highly divided, triangular fronds. The dark green foliage feels as though it is made from a shredded piece of hard plastic. Arachniodes davalliaeformis makes a unique, albeit a slow growing addition to the woodland garden. (Hardiness Zone 7a -9b, at least)

Arachniodes miqueliana (Miquel’s Spider Fern) This easy-to-grow species is a favorite of fern guru Dr. John Mickel. It is similar in form to the beloved Arachniodes standishii, with 2’ long arching lacy fronds that are extraordinarily wide at the base. The fronds are extremely lacy in appearance due to the extreme dissection. The slowly creeping (not weedy) rhizomes form a superb patch. Just as with its relative Arachniodes standishii, Arachniodes miqueliana is very late to drop its foliage for the winter. (Hardiness Zone 5-8a)

Arachniodes simplicior ‘Variegata’ (East Indian Holly Fern) This fabulous 18” by 18” easy-to-grow evergreen fern features a wide streak of yellow down the center of each plastic-textured leaf.  Yes, it looks like it could easily be found among plastic roses and other wire-stemmed plants in that aisle of the craft store. It makes a wonderful accent plant in the shade garden where a bright streak of pale color lifts the overall mood. After cold winters, it can take a long time for the new fronds to reflush but don’t give up, it has proven to be quite winter hardy for us. (Hardiness Zone 7-9 possibly colder)

Arachniodes simulans (Similar Upside-down Fern) This is a wide-ranging (Bhutan, India, China, Japan) fern that’s found on moist forested slopes from 1,500’ to 9,000’ elevation. In the garden, it forms a slowly expanding clump of lacy foliage that’s tardily deciduous, with leaves generally fading by January. The term “simulans” refers to it being similar to another species, in this case A. standishii, though it is quite distinct. This fern produces fronds that are more triangular in outline and darker in coloration than A. standishii. The fronds for us have reached 3’ long and due to their arching nature are held 1-2’ above ground level. Our original plant of Chinese origin is now 15” tall x 2’ wide. (Hardiness Zone 7b-9b, at least)

Arachniodes standishii (Upside-down Fern) This is probably the most sought-after fern by gardeners worldwide and certainly ranks in our top 10 most beautiful garden plants of all time. The lacy, highly divided 18” long fronds rise from a thick, slowly creeping rhizome. It is tardily deciduous with fronds generally starting to decline in January. Our 18-year-old clumps are only 3-4’ wide, but when hiking across one of the Korean islands, I have seen entire forests carpeted in this amazing fern. This was virtually unknown in commerce, due to the limited availability of spores, which don’t mature until December or January, but recent advances in tissue culture have improved availability. The name Upside-down Fern comes from the unusual nature of the frond — it looks like it has been turned upside down as the veins are prominent on the upper rather than lower surface (as is typical in most ferns). (Hardiness Zone 4a-8a)

Arachniodes standishii ‘Mt. Daisen’ (Mt. Daisen Upside-down Fern) is a 2023 Plant Delights/JLBG introduction of a 1978 US National Arboretum collection (USNA 45013.H) made by the late Dr. John Creech in Honshu prefecture on Japan’s Mt. Daisen at 3,400’ elevation. Like typical Arachniodes standishii, this clone forms a stunning, tardily deciduous 18” tall patch of very lacy green foliage... one of the most elegant garden ferns in existence. In moist to average soil moisture, upside down fern will make a 3-4’ wide dense patch in 10 years.

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