How to Care for Western Red Cedar

Western red cedar (Thuja plicata) is a fast-growing, richly aromatic evergreen conifer with soft, flattened sprays of scale-like foliage. It makes an excellent tall specimen, windbreak, or dense privacy hedge and is one of the easier large conifers to grow in cool, moist climates.

Light

Western red cedar grows well in full sun to partial shade. Full sun gives the densest, most compact habit for hedging, while it also tolerates considerable shade better than most conifers, retaining foliage on lower and inner branches. In hot regions some afternoon shade helps prevent foliage scorch.

Water

This species prefers consistently moist soil and is not truly drought-tolerant. Water young and newly planted trees deeply and regularly, especially through dry spells, to keep the root zone evenly moist. Established trees still appreciate supplemental water in summer droughts, when stress shows as browning foliage. It even tolerates seasonally damp ground, though not permanent standing water.

Soil & Potting

Plant in deep, fertile, moisture-retentive soil. Western red cedar tolerates a wide pH range and handles heavier soils better than many conifers, provided there is not constant waterlogging. Enrich poor or sandy ground with organic matter to improve moisture retention, and mulch generously over the root zone to keep roots cool and damp.

Humidity & Temperature

It thrives in cool, humid, temperate climates with mild summers and reliable moisture, echoing its Pacific Northwest origins. It is very cold-hardy and handles snow well. Hot, dry, low-humidity conditions are its main weakness and cause foliage browning, so it performs best where air stays reasonably moist.

Feeding

Feeding needs are modest. In average soil little is required; on poor ground apply a balanced or evergreen slow-release fertilizer in early spring to support vigorous growth. Avoid late-season feeding, which pushes tender growth before winter. A yearly topdressing of compost and organic mulch usually keeps trees lush.

Propagation

Western red cedar propagates readily from semi-hardwood cuttings taken in late summer to autumn; treat with rooting hormone and keep them in a humid, well-drained medium until rooted. It can also be grown from stratified seed, though named cultivars are propagated from cuttings to stay true to type. Layering of low branches can occur naturally.

Repotting / Pruning

Western red cedar responds beautifully to pruning, which is why it is a favorite hedging plant. Trim hedges in late spring and again in summer to maintain shape and density, cutting within the green foliage since it does not reliably resprout from old bare wood. Specimen trees need little more than removal of dead or damaged limbs. Shift container plants up before they become root-bound.

Common Problems & Pests

The biggest issue is foliage browning from drought, root stress, or transplant shock. Bagworms, spider mites in hot dry spells, and cedar leaf blight or tip blight fungi in wet, crowded conditions can appear. Root rot develops in poorly drained, waterlogged soil. Steady moisture, good spacing, and airflow prevent most problems; normal seasonal browning of interior needles is harmless.

Seasonal Care Tips

Plant in autumn or spring while soil is cool and moist. Water deeply through the first summers and mulch to lock in moisture. Shear hedges in late spring and midsummer, and give established trees extra water during droughts. In winter, brush heavy snow off hedges to prevent splayed, broken branches.