The ‘Fern Table,’ My Way

This is my first attempt at building a fern tray, constructed a few days ago. It includes a dwarf Asplenium x ebinoides, known as Dragon’s Tail Fern, and an Asian Pteris ensiformis, or table fern, along with mosses from our garden. Stones were picked up along the Outer Banks of North Carolina.

There is an inspiring feature about fern tables in the current Horticulture Magazine, written by Richie Steffen. Steffen is the Executive Director of the Elizabeth C. Miller Botanical Garden in Seattle, Washington and President of the Hardy Fern Foundation. I’ve read the article through a few times now and studied the illustrations for ideas. It is an excellent overview of fern tables and I highly recommend reading it if you love ferns and enjoy container gardening.

A fern table is a representation of the forest floor, built up from a flat surface. The arrangement typically includes small to medium sized ferns, mosses, shade loving woodland perennials, small shrubs, vines, bits of old wood and rocks. Fern tables may be built directly on a tabletop, on a concrete paver, or on a tray.

These fern tables are designed as permanent outdoor installations, built on concrete bases and measuring several feet square. They are very natural and rustic. They may be used indoors or on a porch or patio, as a centerpiece or runner on a table, or may be placed in the garden as a focal point.

This form takes elements from bonsai, from kokedama balls, and from container gardening to create something new and different. Built up from a solid but flat surface, these displays look a bit illogical and perhaps a bit dangerous. One must break a few gardening ‘rules’ to create them. But they are also whimsical and fun. I wanted to try to create arrangements in this style.

Before investing in concrete blocks and pavers and building something permanent in the garden as a gift for my squirrel friends, I decided to experiment on a smaller scale. So I found some simple Bonsai trays to use as a base. These are entirely portable and may be used indoors or out on our deck. My rectangular trays are 8″ x 10″ and have a shallow side, perhaps a half inch deep. Perhaps I should call my arrangements ‘Fern Trays’ rather than ‘Fern Tables.’

The base is in a shallow box balanced on a flower pot. Much like a cake decorator turns their cake on a rotating cake stand, I find it easier to work by turning the work frequently to access all sides..

I used rocks picked up on long walks along the beach, and didn’t try to find sticks or driftwood in scale for such small trays. My first arrangement uses stones picked up along the Outer Banks of North Carolina, and the second one is made with rocks, and some shells, I picked up along the Oregon Coast. Steffen suggests that all of the stone used in an arrangement be somehow related and of similar type. The same could be said of wood used in the design.

Vermiculite is the puffed rock of gardening. Extremely light-weight, it absorbs water and then releases the moisture when needed.

I used a base layer of vermiculite to help control hydration. Vermiculite is heated volcanic rock. Flecked into very small bits, it can absorb water, like perlite, and later release the moisture as needed. Using it under the entire arrangement allows moisture to wick to where it is needed.

These stones came from Oregon beaches, when I last visited in 2019. They are from ancient volcanic eruptions.

The planting medium must hold together, but also have a coarse enough texture to allow air to penetrate to the plants’ roots. Steffen recommended a mix that includes fine pine bark, coarse finished compost, sand and fine gravel. He doesn’t recommend using a commercial mix with perlite, since perlite can be unsightly. I believe that the clay used in kokedama balls would also be appropriate.

I used what I had on hand, but chose to recycle mixes of potting soil, poultry grit, fine gravel, and sand that I had used previously in pots where the plants had ‘passed on’ to the ‘great greenhouse in the sky.’ In other words, I had some old pots of good mix where the plants hadn’t made it through the winter. I emptied out all of these old pots into a tub and thoroughly wet the soil mix before beginning. This gave a coarser than usual mix that still contains some peat, fine bark, and perlite. It is a good idea to add some time release fertilizer, like Espoma Bio-Tone, when mixing the soil.

This Korean Rock fern, a Polystichum, is very adaptable. It is hardy in our area and will remain relatively small.

Do you remember the scene in Spielberg’s ‘Close Encounters’ movie where the Richard Dreyfuss character is trying to sculpt Devil’s Tower, in Wyoming? That is how I felt spooning the wet soil onto the vermiculite covered tray. I built up a ‘tower’ of soil, slightly off center, to support the first fern.

I used a variety of small ferns from 1.5″ pots, sold for use in terrariums. Some of these are ‘footed’ or creeping ferns, others clumping. Some of these can grow to a foot or more tall, over a couple of years, in optimum conditions. I will be interested to see what these ferns can do planted in this way. I also had a rooted division of a ‘footed’ fern that has been growing across my windowsill for the past several years, and a baby that just began growing out of some moss in my backyard. It has come along naturally from dropped spores.

This ‘Rabbits Foot Fern,’ Davallia fejeensis, has a hairy rhizome that creeps along above the soil line. New fronds emerge along the length of the rhizome. Eventually, the soft brown rhizomes will network across the entire arrangement. This is another small fern that won’t grow to more than a foot tall.

Building the arrangement is spontaneous. With a collection of materials, and a rough idea of what the result might be, one just places the stones, any driftwood, soil, and plants. I worked with the plants from the center, outwards, adding soil to eventually cover the entire tray. My ferns were tender enough that it was easy to reduce the root ball by gently knocking off excess soil, making them easier to ‘plant’ and work into the design.

Another footed fern has a small cluster of roots tucked in under a stone. It will also creep, and root where its rhizome contacts the soil.

Once all of the plants are placed, firm up the soil, fill in any spaces between root balls, and finalize placement of the stones. I used a bit of fine aquarium gravel along some of the edges and around stones.

Small ferns are sprouting in mossy areas of our garden this spring. I managed to lift a baby fern with this piece of moss. Carefully pull out any grass, twigs, or dead materials from each hunk of moss before placing it on the fern tray.

Steffen recommends using site local mosses. If your arrangement is kept outdoors, spores will also begin to colonize, so you may end up with a greater selection of mosses than you begin with. I have been cultivating moss here for the last many years, so there is a good selection.

Always lift fairly small chunks of moss so that spores and natural growth can quickly fill in the bare spots. We’ve had hot weather, so our moss was a bit dry as I lifted it. It quickly absorbs water and greens up. If your moss is dry, soak it, or mist it, so it springs back to its normal volume and softness.

Mosses don’t have roots. Even though they can ‘attach’ to soil, wood, masonry and stone, mosses don’t have a traditional vascular system. Every cell can absorb water and pass it on to its neighbor. When using fresh moss, press it firmly onto the soil so it makes contact, and water it gently. Even the smallest pieces can be pushed into small spaces and will grow. You can use moss covered rocks, but it is smart to lift mosses that have already been growing on soil to use to cover soil in a container arrangement.

The best way to keep mosses healthy and growing is to keep them moist. They can use humidity and dew outside. Indoors, you will need to mist them or otherwise gently water them daily. The mosses will absorb moisture from the soil they cover, too. The shallow tray means that water can collect in the vermiculite, and then wick back out into the soil and plants, as needed.

I covered all of the soil with moss and stone. This is a final opportunity to sculpt the final contours of your design. Stone and wood could be placed in the center of the design if you have an interesting piece you want to use. I was working with relatively small stones, so I used mine around the edges. I”m going to watch for some small sticks with lichens growing on them, to add as accents.

These arrangements are very flexible, at first. If, after looking at it for a few days, you want to make a change, you can easily remove, move, or add elements. Once the plants’ roots begin to grow in, that will become more challenging. Eventually, roots should run through most of the soil, making this arrangement fairly solid. But you can still add or remove elements to replace unhappy ferns and keep the scene fresh. Including a woody seedling tree or dwarf shrub gives the design even more stability and multi-season appeal.

Water the work as you go, using the water to settle the moss, clean off the rocks, and help the plants settle properly into the soil.

I have used mostly tender ferns, so my arrangements will need to winter indoors. Once they grow in and firm up a bit, I can move them out to a shady spot on the deck, where I’ll remember to keep them watered. Our birds and squirrels have proven to love to pick through mosses, however. They may be pinching some for their nests, or looking underneath for bugs or treasure. I can only imagine what a curious squirrel would do with one of the ‘Fern Trays’ given the opportunity. So mine are inside, near a window, for now.

Ferns are a great choice for this design, but only one of several good choices. Miniature Hostas, Cyclamen in season, miniature ivy or Ficus vines, Begonia rex, Sedum, Oxalis, Saxifraga, and other small perennials would work well. Steffen’s Fern Tables live in the Pacific Northwest, near Seattle, where the climate is very different than here in coastal Virginia. Plant choice must reflect what is reasonable in the climate.

The baby fern I lifted in the moss looked a bit droopy, but perked up overnight. The moss has already responded to watering. I like to leave the arrangements alone for a few hours after completion, before moving them into their new locations.

Consider making a ‘Fern Tray’ as a centerpiece for a special event, as a landscape in a small indoor living space, as a gift for a gardener friend, or just for the fun and entertainment of making it. If you are attracted to sandy Zen and stone gardens, you might find this living moss garden a pleasant, meditative activity. Caring for it cultivates peaceful mindfulness.

You may find that you already have many of the necessary materials on hand, as I did. I considered these two arrangements as ‘proof of concept’ trials before I order those concrete blocks and pavers for the fern garden. I really would love to have a larger, outdoor ‘Fern Table’ like the ones featured in Steffen’s article. The question is, can I cultivate one here in my coastal Virginia Forest Garden, with our rainstorms and abundant wildlife? Time will tell….

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To Learn More:

Building a Fern Table by Richie Steffen ( .pdf on the Elizabeth C. Miller Botanical Garden website)

Fern Table, Materials and Care by Richie Steffen

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