Soft tree fern

Sun

Partial shade or bright, filtered shade; protect from hot afternoon sun and drying winds.

Water

Keep the root zone consistently moist but not waterlogged. In warm weather, also wet the fibrous trunk and crown, especially on newly planted specimens.

Soil

Humus-rich, moisture-retentive soil with good drainage; acidic to neutral soil is best.

Height

12-20 ft (3.7-6 m) in gardens over many decades; taller in its native habitat.

Spread

8-13 ft (2.4-4 m)

Foliage

Evergreen. Large, finely divided, arching green fronds, often 6-10 ft (1.8-3 m) long, above a trunk clothed in reddish-brown fibres and roots.

Growth

Slow; an established trunk usually gains only a few centimetres each year.

Care needed

Medium

• Deer resistant
• Wildlife
• Low allergen

Northern hemisphere months. In Australia, shift them by six.

Difficulty

Hard

Toughness

Needs looking after

Pick your zone, country, light and whether you have pets.

1. Planting day

   1.9 ft (0.58 m)

2. After 1 year

   5 ft (1.5 m)

3. After 2 years

   8 ft (2.4 m)

4. After 3 years

   11 ft (3.2 m)

5. After 5 years

   16 ft (4.9 m)

   full size

About 5 years to full size.

From a typical nursery size, at an average rate for this kind of plant. A rule of thumb, not a forecast.

Cats and dogs

Safe

Growth rate

Slow

• Water deeply during dry spells; newly planted trunks need especially close attention until roots establish.
• Wet the trunk and crown in warm, dry weather, but avoid leaving water pooled in the crown during freezing weather.
• Apply a balanced liquid fertiliser at half strength monthly during active growth to established plants.
• Mulch the root zone with leaf mould or compost, keeping the trunk base clear of a thick, wet heap.
• Shelter from strong wind and allow enough room for the full spread of the fronds.
• Before frost, loosely insulate the crown with dry straw and breathable fleece; remove protection when mild weather returns.

Pruning. In spring, cut off fully brown or frost-killed fronds close to their bases without cutting into the trunk or crown. Leave healthy green fronds in place, and never cut back the growing tip.

Spring

Remove winter protection gradually and check the crown for emerging fronds.

Spring

Remove dead fronds, refresh the mulch and plant new specimens after the risk of hard frost has passed.

Late spring

Begin dilute feeding once new growth is active.

Summer

Check moisture frequently and water the soil, trunk and crown during dry weather.

Autumn

Stop feeding and prepare breathable frost protection.

Winter

Protect the crown during frost and keep the root zone from drying out without saturating cold soil.

• Use as a focal point in a sheltered woodland garden, with lower ferns beneath it.
• Place in a shaded courtyard where the trunk and spreading crown create a strong architectural shape.
• Combine with hostas and other broad-leaved shade plants for contrasting foliage textures.
• Plant beside a shaded path or seating area where its crown can spread overhead without obstructing access.

Garden styles it suits: Woodland, Architectural minimal, Modern tropical, Australian native, Secret garden and Green on green.

Plant it with: Hostas, Soft shield fern, Hart's tongue fern, Japanese painted fern, Bergenias and Astilbes.

Wildlife: The fibrous trunk can support mosses and provide shelter for small invertebrates. As a fern, it produces no nectar or pollen for pollinating insects.

• Brown, crisp fronds usually indicate dry soil, low humidity or hot wind: water thoroughly and provide shade and shelter.
• Frost can kill fronds and damage the growing point: protect the crown before freezing weather and avoid removing damaged fronds until spring.
• Crown or root rot can follow stagnant, waterlogged conditions: improve drainage and avoid persistent saturation, especially in cold weather.
• Slugs and snails may damage emerging croziers: inspect new growth and use hand-picking or locally approved controls.

Not known to be toxic to cats, dogs, horses or people, and no part is recognised as a significant poisoning hazard. Species-specific safety information is limited; do not treat the fronds, trunk or spores as food.

• Rough tree fern (Cyathea australis)

  Its frond stalk bases are rough and scaly, often with prickles; soft tree fern has softer, hairy stalk bases and a densely fibrous trunk.

• Wheki (Dicksonia squarrosa)

  Usually has a slimmer, dark trunk, dark wiry frond stalks and a smaller crown; it often produces shoots around the base, unlike the normally single-trunked soft tree fern.

Dicksonia honours Scottish botanist James Dickson, while antarctica refers to its southern origin rather than to the continent of Antarctica.

Propagation. Propagate from spores under warm, humid, clean conditions; raising a trunked plant takes many years. This species does not normally produce offsets for division. Buy nursery-propagated or legally sourced plants rather than wild-collected trunks.

Accepted botanical name

Dicksonia antarctica

Sources: GBIF (CC BY 4.0). The care and design notes are LandscapeGPT's own.