Nothing else brings the prehistoric to a British garden like a tree fern. The single most important thing to understand about Dicksonia antarctica is that the trunk is not wood — it's a living mass of roots, and it drinks. Care for the trunk and the fronds look after themselves.
Position
Shade or dappled light, sheltered from wind — the conditions of a forest floor. A shaded courtyard, a north-facing corner, under the canopy of larger trees: anywhere bright sun and drying wind can't reach the fronds. The more sheltered and humid the spot, the more lush and enormous the fronds grow.
Watering — the trunk, not just the pot
Through the growing season, water the trunk itself: a can poured slowly over the top so it soaks down through the fibre, daily in hot dry spells, a few times a week otherwise. Keep the crown (the growing point where fronds emerge) moist in summer too. The soil or pot needs watering as well, but a tree fern watered only at the base is a tree fern slowly drying out from the top.
Winter protection
Hardy to around −5°C once established, and reliably fine in sheltered London gardens with basic care. Before hard frosts, pack the crown loosely with straw or dry bracken to protect the growing point — that crown is the whole plant's future. In a prolonged freeze, wrap the upper trunk and crown in fleece. Unwrap promptly when the cold passes so the crown doesn't sit damp. Fronds burned by a hard winter can be cut off; a healthy crown pushes a complete new flush of croziers in late spring.
Feeding
A dilute liquid feed monthly from late spring to early autumn, applied over the trunk and root zone, keeps the fronds deep green and full-sized.
In pots
Tree ferns do well in generous containers with a rich, moisture-retentive compost. The trade-off is that everything above — watering, winter root protection — matters a little more, because the plant can't reach out for its own moisture.
Good to know
Growth is around 2–3cm of trunk a year, which is why a tall tree fern is a decades-old plant and priced accordingly — like our Yucca rostrata, you buy the size you want rather than growing into it. Don't be tempted to test the crown by pulling emerging croziers; they're soft, and they're the entire year's growth.
