The Victorians popularized ferneries, planting ferns in stone grottoes or "stumperies"—arrangements of upturned tree roots. They created indoor ferneries in conservatories or in semi-underground glass-roofed structures. Using a conservatory on the side of the house is possible, but it must be shaded and constantly cooled with running water or sprinkler systems. An outdoor fern house in an arbor requires only a sheltered site with filtered sunlight. Stones, stumps or stone structures within the fernery help provide shade and give the appearance of a Victorian fern house.
Things You'll Need
Standard wood arbor, lean-to greenhouse or small conservatory
Tree stumps or logs
Water feature (pond liner or fountain)
Soaker hoses or sprinklers
Choose the site. The east side of the house where it will receive morning sun or a side already shaded by trees is best. Avoid the south wall, since this will be too hot.
Choose a commercially available lean-to greenhouse, conservatory or wood arbor. Erect this against the house per manufacturer's instructions. If you want an arbor to provide weather proof seating, add a roof, but the ferns will prefer being open to the rain.
Provide shade and for outdoor fern houses a windbreak--plant large shrubs or small trees nearby. Grow climbing plants over the structure or add greenhouse shading. In summer an arbor can be draped with dark-colored shade cloth.
Dig a hollow within this structure, so your fernery is a sunken garden. Planting ferns in a hollow helps create a stable environment where they can be kept damp and cool. The surrounding earth insulates the ferns from winter cold. If building an open-sided outdoor fern house, these banks provide a wind break. Pile the extracted earth around the rim of the hollow for added depth.
Install a water feature. This can be running water, a fountain or pond. The presence of water helps keeps humidity high. Running water increases the fernery's visual attractiveness and adds pleasing sounds. Alternatively install soaker hoses or a sprinkler system—particularly important if using a conservatory as fern house.
Mark out beds for planting. Fill beds with any mix of composted pine bark, ericaceous compost, leaf mold or orchid compost, providing a light, moisture-retentive, mildly acidic growing medium.
Set rocks or stumps into the beds and walls of the hollow. Building an uneven rock wall helps keep conditions shady and cool and provides useful niches for planting.
Choose a selection of ferns of contrasting size and shape. Include some other moisture loving plants—astilbes, hostas--for contrasting shapes.
Soak new ferns in buckets of water overnight before planting. Use rainwater if possible.
Plant ferns, so the crown, the solid base of the plant from which the shoots grow, is barely above ground level.
Water well. Continue to water daily until established. Conservatories will need twice daily watering all summer.
Apply mulch twice yearly. If using sprinklers, take care not to scorch leaves by watering in the heat of the day—particularly under glass.