Coast redwood

Coast redwood: how do you recognise it?

Habit

Straight trunk with a narrow, conical crown; in gardens up to 30 m tall and 8–10 m wide. Old trees develop a broad trunk base.

Leaves

Flat, soft needles 1–2.5 cm long in two rows along the shoots: dark green above, blue-green with two white bands beneath.

Cones

Small, egg-shaped cones about 2–3 cm long.

Bark

Thick, soft, fibrous and reddish-brown; tens of centimetres thick on old trees.

Roots

Shallow and wide-spreading, with no taproot. It therefore needs moist soil and shelter from storms.

Plants: April–May and September · Pruning: April

Why grow it?

• Grows fast and becomes an impressive, almost prehistoric eye-catcher in a park or large garden.
• Soft, evergreen foliage that gives atmosphere and shelter all year.
• Thick, soft, reddish-brown bark that stands out nicely against the green.
• Can resprout from the trunk or base after damage or frost, unlike most conifers.
• Low maintenance: no pruning and few diseases, if it has the right spot.

Coast redwood: where does it grow best?

• Sun to partial shade; plenty of light gives the best growth, but humid air and cool roots matter.
• Deep, humus-rich, moisture-retentive sandy or loamy soil, acid to neutral. Avoid chalky soil.
• Moderately moist to wet: it dislikes drying out, but not standing water.
• Shelter from cold, dry east winds and storms; avoid a frost pocket where cold air collects.
• Allow at least 8–10 m of space, away from houses, drains and pipes.

Light

Sun and partial shade

Soil type

Sand or loam

Acidity

Acid or neutral

Moisture

Normal or wet

Size

30 m tall, 10 m wide

Hardiness

Hardy (to -15 °C)

Goes well with

• Soft shield fern: Evergreen fern for the moist shade at the base.
• Rhododendron: Likes the same moist, acid soil and light shade.
• Hosta: Large leaves in the shade under the tree.
• Hydrangea: Flowers in light shade and likes moist soil.
• Japanese maple: Fine foliage that contrasts with the dark needles.

Coast redwood: when and how to plant it?

Plant in April–May and September.

1. Plant in April–May or in September, when the soil is not too dry and no longer freezing.
2. Choose a young plant of 0.5–1.5 m: it establishes better and keeps growing fast.
3. Dig a hole twice as wide as the root ball and just as deep. Loosen the sides.
4. Mix the excavated soil with compost or leaf mould, without fresh manure.
5. Plant at the same depth as in the pot, firm in and water with 15–20 litres.
6. Spread a 5–8 cm layer of wood chips or leaf mould around the base, keeping it clear of the trunk.

Care

Water

In the first year, weekly in dry spells; also later, water deeply in prolonged drought. It likes moist soil and air: drought browns the needle tips.

Feeding

In spring, a layer of compost; an organic fertiliser for conifers is fine.

Mulching

Every year 5–8 cm of mulch to keep the root zone cool and moist, especially on young trees.

Shelter

In the first winters, put a hessian or reed screen on the east side of young trees.

Tip: Choose a sheltered spot with deep, moist soil and do not plant it too close to the house: it gets enormous. Protect young trees from cold east winds in the first winters.

Coast redwood: when to prune it?

Pruning months: April.

When: Pruning is usually not needed: it grows into a conical shape by itself. Do the small jobs in April.

How:

• Remove dead or damaged branches back to the trunk.
• If there are two leaders, choose one and remove the other in spring, while the tree is young.
• After frost damage, wait until May–June before removing brown shoots: it often regrows.

Caution: Never remove the top: the tree would form several tops and lose its straight shape.

Pruning: when and how · Pruning calendar and basic rules

Propagation

Seed

Sow in March–April in acid, sandy seed compost, after keeping the seed cool and moist for a few weeks. It germinates within a few weeks. Seedlings can differ from one another.

Cuttings

Cuttings of young shoots in September–October in moist sand under plastic root slowly, after a few months. Usually a job for nurseries.

Coast redwood: how does it get through the winter?

Hardy to −15 °C: protect young plants.

• Mature trees are hardy to about −15 °C; in harder frosts, needle tips can turn brown and twigs freeze.
• Protect young trees for the first 3–4 winters: a hessian or reed screen on the east side and a thick mulch around the base.
• After a severe winter, wait until May–June before pruning: the tree may sprout again.

Diseases and pests

• Brown needle tips: Caused by drought, cold east wind or frost. Choose a sheltered spot, mulch and water in dry periods. The tree often recovers in spring.
• Late frost: New shoots in April–May can freeze. Cover young trees with fleece on frosty nights. Only cut brown parts after regrowth.
• Wet feet: Yellow foliage and dying tips in standing water. Choose a free-draining spot or improve drainage.
• Storm damage: The roots are shallow, so large trees can blow over in a severe storm. Choose a sheltered spot and do not plant too close to houses.

Through the year

• January: Shake heavy snow off the branches. Check young trees for frost damage.
• March: Give compost or organic fertiliser. Leave winter protection in place until frosts are over.
• April: Plant. Remove dead branches. Mulch.
• May: Plant. Remove winter protection after the last frost. Water.
• June: Water in dry weather. Cut away damaged shoots now.
• July: Water deeply in dry weather.
• August: Water deeply in dry weather.
• September: Plant. Take cuttings.
• October: Top up the mulch.
• November: Put up a windbreak screen for young trees.

Did you know?

• The tallest known tree in the world is a coast redwood in California, about 115 m tall.
• In its homeland it can live for more than 2000 years.
• It absorbs moisture from coastal fog through its needles, which helps it in dry summers.