A Fern Table

The new fern table, moments after I completed the installation this morning.

Richie Steffen’s article about fern tables, in the current Horticulture Magazine, inspired me to begin experimenting with this planting form, using shallow trays, Bonsai pots, various ferns and mosses to get an idea of how these plantings might work in our climate.  Steffen is the Executive Director of the Elizabeth C. Miller Botanical Garden in Seattle, Washington and President of the Hardy Fern Foundation.

Fern tables elevate a mixed planting of ferns, vines, mosses and other perennials to bring a curated slice of the forest floor closer to the viewer, drawing attention to these often subtle and overlooked plants.  The Fern tables featured in Horticulture grow near Seattle, Washington, where the climate is usually milder and wetter than it is here in coastal Virginia.  They also don’t have tropical inundations that we so often experience this time of year.

My first few plantings were ‘proof of concept’ designs, and I have enjoyed watching them grow over these past few weeks.  They definitely prefer life out of doors in a shady spot to the shelter of our living room, and I’ve needed to give them more and more time outside to keep both ferns and mosses happy.  They have proven stable, portable, and the ferns all show signs of growth.

An earlier ‘proof of concept’ fern table I’ve been caring for at home.

With this small measure of confidence, I began planning a fern table installation for the botanical garden where I volunteer, considering the various design challenges for the last few weeks.  I located a shaded, sheltered spot where several layers of overhanging trees will break any heavy rain and shield the planting from full sun exposure.  I also sourced a piece of slate, and some concrete blocks to elevate it, to provide a base for the table.

The base for the new fern table

We grow a great many different ferns at the Williamsburg Botanical Garden across multiple garden areas.  Still, I didn’t want to dig and transplant any of them in July.   Since the planting is in the edge of the gravel garden, adjacent to one of our native plant areas, it is important to me to use predominantly native ferns in the planting, which meant it is very challenging to shop for ferns of the correct size and type for this project.  Most shops have hybrids and imported species, if they even have ferns left at all this late in the season.

I was happy to find a small native Southern maidenhair fern, Adiantum capillus-veneris, at the Great Big Greenhouse in Richmond over the weekend.  The roots were small enough to introduce into this stye of planting.  Another Southern maidenhair fern grows well in the garden, so I’m confident in using this as the main fern species on the fern table.  I also picked up a tiny tropical Dryopteris cordata for its interesting leaves.

Southern Maidenhair fern, Adiantum capillus-veneris anchors this planting

I had several small volunteer ferns at home still shallow-rooted enough to lift for this project.  Two are evergreen native Christmas ferns, Polystichum acrostichoides, and the other a hybrid Athyrium.

You may be familiar with the European raised bed technique called Hugelkultur, which uses logs, branches, sticks and other compostable materials to build the base of the bed.  The wood gives the bed structure, and acts as a sponge to absorb water, which is then released into the soil as needed.  Additionally, as the wood decomposes, it enriches the soil.  In Europe, a few inches of topsoil are added to a Hugelkultur bed before plants are planted directly into pockets between logs and branches.  Any heat generated by the composting materials in the bed help lengthen the growing season for the plants.

I’m using a modified Hugulkultur base for the planting of this fern table, with decomposing branches found on the floor of our wooded areas.  I also poured a layer of vermiculate onto the slate to absorb moisture.  The soil mix includes half and half shredded bark and commercial topsoil, with a little bit of potting soil mixed in, and a good sprinkle of Espoma’s Bio-Tone to help the plants establish.

Decomposing branches give this planting structure and hold the soil in place on the flat slate base

I expect that the bark, Bio-tone and branches will encourage the growth of mycorrhizal fungi in this planting, further helping to link and support the various ferns.

After placing the largest plant, the maidenhair fern, I built up the area around it and between and around the branches with the soil mix, placing a few large rocks strategically along the edges to help hold the soil.  I also used some crushed granite in places to help stabilize the planting.

As each portion of the planting was finished, I covered that area of soil with sheets of site-native mosses that were soaked in water to help them re-hydrate.  We’ve had some hot, dry weather in recent days.

In addition to the ferns purchased and brought from home, I transplanted a small ebony spleenwort from another container planting and some partridgeberry, Mitchella repens, that was growing nearby.  The partridgeberry is a small native ground cover vine that blooms each spring and produces berries in autumn.  Birds and small animals appreciate the berries.

My main concerns with maintaining this planting are keeping it sufficiently hydrated, and keeping the squirrels and birds from digging through it.  We have a good soaking rain on the way later today, so it will be watered again by sunset.  I’ll return later in the week to check the planting and apply animal repellents to discourage any curious squirrels.

The fern table survived its first heavy rain beautifully, without sustaining any damage from the weather.

I’m looking forward to watching this planting mature over the next few months as the ferns and vines grow into their potential.  The partridgeberry, mosses and Christmas ferns are evergreen.  The Dryopteris will need to come out before frost, and I expect to add a hybrid Asplenium dragontail fern or two by early August.   By autumn, I’ll be tucking in a few bulbs for miniature spring flowers.

If other gardeners have been making fern tables in our area, I’m not aware of the practice.  My hope is that this fern table in a public garden will inspire others to give this planting form a try.  It has been a very entertaining project, and it is built mostly with ‘found’ and locally sourced materials.   The planting can provide habitat for overwintering insects such as native bees and beetles.

This is a beautiful way to raise awareness of our native woodland plants. And, it would make a nice family project for parents of young children who might design a miniature landscape or fairy garden for their little ones’ play.  I hope that others in our community will experiment with this planting style after seeing this modest first attempt at our local garden.

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