Thuja occidentalis

Description

Quick Facts
– Botanical Name: Thuja occidentalis
– Common Name: White Cedar / Eastern Arborvitae
– Plant Type: Evergreen conifer / hedging plant
– Mature Height: Approx. 8-15m in time (slow to moderate growth, much less in the first 10 years)
– Mature Spread: Approx. 3-5m
– Foliage Colour: Fresh mid to deep green in flattened, scale-like sprays; fragrant when crushed, and can bronze slightly in winter
– Cones: Small, upright, clustered cones
– Habit: Dense, narrowly conical to pyramidal, well furnished down to the base
– Hardiness: Fully hardy
– Soil Requirements: Moist, well-drained, reasonably fertile; tolerates clay and chalk but dislikes waterlogging
– Aspect: Full sun to partial shade
– Maintenance: Low to moderate: clip once or twice a year if grown as a hedge

Description
Thuja occidentalis is a tough, reliable evergreen conifer. The flattened sprays of fresh green, softly aromatic foliage form a dense, neat cone that stays full and well clothed right down to the ground, giving good screening and structure in every season.

It is a lovely choice for hedging, boundaries and windbreaks, and it clips well into a smart, formal shape. The foliage holds its colour through the colder months, so the planting still looks fresh when much of the garden has died back.

Hardy, fragrant and wonderfully dependable, Thuja occidentalis is an evergreen that quietly gets on with the job.

Caragh Garden Notebook

Planting:
Plant in autumn or spring in moist, well-drained soil, adding plenty of well-rotted compost to the planting hole. For a hedge, space plants at around 60-80cm apart for dense cover. Choose a sunny or lightly shaded spot, plant at the same depth as the pot, firm in gently, water in thoroughly and mulch to keep the roots cool and moist.

Watering:
Water regularly through the first two growing seasons, especially in dry spells. Thuja dislikes drying out completely, and prolonged drought can cause browning of the foliage, so a deep water in hot weather is worthwhile. A newly planted hedge needs particular attention in its first summer.

Feeding:
Apply a balanced general fertiliser or slow-release conifer feed in spring. A mulch of well-rotted compost or bark around the base helps retain moisture and supports steady growth.

Seasonal Care & Tidy-Up:
For a hedge, trim once or twice a year, in late spring and again in late summer, cutting only into the soft, green, current-season growth. Never cut back into old, brown wood, as it will not regrow and will leave permanent bare patches.

Pests & Problems:
Generally healthy in the right position. Waterlogged soil is the main risk and can lead to root rot, which shows as browning foliage and general decline. Winter wind or drought can cause browning in exposed spots, so a sheltered position helps. Wear gloves when trimming, as the foliage can irritate sensitive skin.

Design Notes:
Thuja occidentalis is an excellent choice for privacy hedging, boundary screening and windbreaks. It also works as a formal accent, for example a pair either side of a gate or entrance. The fresh green foliage makes a smart backdrop for borders, roses and seasonal planting.

Propagation:
Take semi-hardwood cuttings in late summer, or grow from seed. For uniform, reliable hedging, source nursery-grown plants.