Ferns for Small UK Courtyards: A Seasonal Planting Plan

A courtyard five metres square can feel like a corridor of grey paving and fence panels. Ferns change that without demanding much room. They grow upwards rather than outwards, they cope with the shade that narrow spaces create, and most will sit happily in a pot for several years before needing to be divided. Choose for the light you actually have, then stagger the plants so something is unfurling, colouring or holding its shape in every season.

Read the space before you buy anything

Spend a day watching your courtyard rather than shopping. Note when direct sun arrives, how long it stays and which wall it comes from. A north-facing yard with a couple of hours of morning light is genuinely a fern courtyard. One that bakes from noon until six is not, unless you keep your planting to the shadiest strip and accept that pots will need watering most evenings in July.

Wind matters as much as sun. Narrow gaps funnel it, which dries compost quickly and shreds delicate fronds. If your courtyard is a wind tunnel, plan for tougher evergreens and put the fragile ones behind a pot or a low screen. Shelter and reliable moisture decide success here far more than soil does.

Compact ferns that earn their pot space

These all stay manageable in a three to five litre pot and are widely sold in the UK. Check the label for hardiness before buying anything unusual.

• Asplenium scolopendrium (hart's tongue fern) — evergreen straps of bright green, upright and architectural. Tolerates lime and dry shade once established, and looks good in a pot for years.
• Polystichum tsus-simense (Korean rock fern) — small, dark and evergreen, slowly forming a neat shuttlecock. One of the best ferns for a small pot and it shrugs off a dry spell better than most.
• Blechnum spicant (hard fern) — a low rosette of narrow evergreen fronds with upright fertile spikes in summer. Neat, unfussy and good at the front of a group.
• Dryopteris erythrosora (Japanese shield fern) — new fronds open coppery pink in spring and again after a mid-season cut-back. Semi-evergreen and useful at mid-height.
• Athyrium niponicum var. pictum (Japanese painted fern) — silver and burgundy, deciduous, and best with steady moisture and no midday sun.
• Cyrtomium fortunei (holly fern) — leathery, evergreen and notably tolerant of dry shade under a wall.
• Adiantum venustum (Himalayan maidenhair) — fine, delicate and deciduous, spreading gently where it is damp and sheltered.

A seasonal plan for a small courtyard

Spring: divide, repot, watch the croziers

March and April are for lifting and splitting anything that has filled its pot, and for repotting into fresh compost. This is when ferns are at their most interesting: tight coils of croziers unfurling over a few warm days. The painted fern's colour is best now, before summer heat dulls it. Feed lightly from April, and top-dress pots with a centimetre of leaf mould or bark.

Summer: water is the whole job

From June, check pots every morning in hot spells. Water the compost rather than the fronds, and water early so the roots have moisture before the day heats up. Grouping pots helps: foliage shades the compost and keeps root balls cooler. If you must move anything, move the small pots into shade and leave the established plants where they are. A saucer under a thirsty fern in July is forgiven; left in place through winter it is not.

Autumn: the best planting window

September and October beat spring for planting, because the soil is still warm and rain does the watering. Clear fallen leaves out of the crowns as they drop; a soggy leaf sitting in the middle of a fern over winter can rot the growing point. Leave evergreen fronds alone. If vine weevil has been a problem in your pots, this is the moment to deal with it while the soil is warm, using a biological control watered into the compost.

Winter: rely on the evergreens

Hart's tongue, Korean rock fern, hard fern and holly fern carry the structure from November to March, so give them the positions that read best from the house. Raise pots onto feet or bricks so surplus water drains away and the compost does not freeze solid. Keep pots of borderline-hardy ferns against a sheltered wall. Cut back the dead fronds of deciduous ferns in late winter, once you can see new buds forming at the crown.

Compost, pots and feeding

Use a loam-based or peat-free multipurpose compost mixed with roughly a quarter bark or leaf mould and a handful of grit. Ferns are light feeders: too much nitrogen gives soft, floppy fronds and pale colour, which rather defeats the point. A diluted liquid feed every four to six weeks from April to August is plenty. Terracotta dries out fast; glazed or plastic pots hold moisture longer and keep roots cooler. Whatever you choose, it needs drainage holes and something underneath to lift it clear of the paving.

Rainwater is ideal, though tap water suits most ferns and hart's tongue actively likes lime. Avoid splashing hard water over the fronds, which leaves chalky marks on glossy leaves.

Making a narrow space feel wider

• Layer by height: taller ferns at the back, low rosettes at the front, with a shelf or wall bracket for a third tier.
• Repeat two or three species rather than buying one of everything. Repetition reads as design; a row of singles reads as a collection.
• Let pots touch so the foliage knits together instead of sitting in isolation.
• Use the walls. Asplenium trichomanes and Polypodium vulgare will grow in pockets in a dry-stone wall or a planted crevice.
• Leave one plain surface alone. A bare pale wall makes the green beside it look deliberate.

Start with three pots

You do not need a plan on paper. Buy three ferns: one upright evergreen such as hart's tongue, one small evergreen such as Korean rock fern, and one deciduous plant for colour, such as the Japanese painted fern. Put them in the shadiest spot you have, water them properly through their first summer, and see where the light actually falls across the year. Next spring you will know exactly what to add.

Photo: Jane Blaze / Pexels