Western red cedar (Thuja plicata 'Aurea')
Thuja plicata 'Aurea' is a vibrant needled evergreen Western red cedar cultivar offering soft yellow summer foliage. Ideal for screens or specimen planting in zones 5-7.
Complete Plant Information
Overview
The Thuja plicata ‘Aurea’, a stunning cultivar of the native Western red cedar, offers gardeners a magnificent vertical accent characterized by its soft, appealing yellow foliage displayed throughout the summer months. While related to the towering species found in the Pacific Northwest, this variety maintains a manageable, though still substantial, stature, making it excellent for screens or stately specimen planting. It provides year-round evergreen interest, contrasting beautifully against darker plantings in the landscape.
This conifer thrives best when provided with consistent moisture and fertile soil, reflecting its origins in cool, damp forest areas. Gardeners should note that while it prefers full sun for the best color, Thuja plicata ‘Aurea’ appreciates light afternoon shade, particularly in intensely hot summer climates. Successful cultivation relies on meeting its medium water needs and understanding its specific soil preferences.
Functionally, the Thuja plicata ‘Aurea’ serves as an outstanding privacy hedge or a dramatic backdrop due to its height potential and dense, aromatic needles. Choosing this golden cultivar allows gardeners to incorporate the robust structure of the Western red cedar while adding a desirable warmth to the overall garden composition. Always assess your local climate before planting, as this species can struggle in regions outside its optimal cool-summer range.
Fast Facts
- Plant Family: Cupressaceae
- Plant Type: Needled evergreen
- Hardiness Zones: USDA Zones 5-7
- Size at Maturity:
- Height: 40-50 ft
- Spread: 10-15 ft
- Bloom Time: Non-flowering
- Bloom Description: Non-flowering
- Sun Exposure: Full sun to part shade
- Water Needs: Medium
- Maintenance Level: Medium
How to Grow
Planting the Thuja plicata ‘Aurea’ is best done in the spring or fall when temperatures are moderate, allowing the roots to establish before summer heat or winter freezes. Site selection is crucial; choose a location with moist, fertile, well-drained soil. These trees are intolerant of dry conditions, so avoid highly exposed, baking sites.
Watering should be consistent, especially during the first few years after planting, to maintain medium moisture levels; drought stress is poorly tolerated by this cultivar. While heavy fertilization is usually unnecessary for mature specimens, an annual application of balanced fertilizer in early spring can support vibrant yellow color. Pruning is generally minimal, primarily for shaping screens or removing errant branches.
This variety particularly thrives in cooler summer climates, mirroring conditions found in its native habitat. In warmer regions, ensure afternoon shade is provided to prevent foliage scorching. Gardeners should be mindful that environmental conditions significantly outside the native range, such as the heat and humidity often found in areas like St. Louis, may challenge the vigor of this Western red cedar.
Landscape Uses
The upright, dense habit of Thuja plicata ‘Aurea’ makes it highly versatile in landscape design. Its height potential targets it perfectly as a large specimen tree on spacious lawns where its golden hue can anchor a view. When planted in succession, these trees create magnificent, screening hedges or screens capable of providing decades of privacy and seasonal beauty.
Consider using the Thuja plicata ‘Aurea’ as a dramatic background element behind perennial borders, allowing the yellow foliage to illuminate darker green or purple-leafed companions. Its preference for moist soils also makes it an excellent structural component within a planned rain garden design, helping to manage runoff effectively. Young trees are particularly suited for formal hedge work if kept pruned.
Standout Features
Noteworthy Characteristics
Thuja plicata, commonly called western red cedar or giant red cedar, is native to the Pacific Northwest where it is typically found in cool but moist forest areas and bottomlands from southern Alaska along the Pacific coast to northern California and in the northern Rockies from British Columbia to Montana. This is the largest tree in the cypress family, growing in its native habitat to 100-200’ tall and living from 400 to 1000+ years. Specific epithet means pleated. The ‘Aurea’ cultivar grows somewhat smaller than the species and features soft yellow foliage throughout the summer, marked by aromatic, scale-like needles and fibrous, reddish-brown bark.
Tolerances
- Clay Soil
- Black Walnut
Potential Problems
The Thuja plicata ‘Aurea’ generally exhibits good resistance, lacking any reported serious insect or disease issues. However, vigilance against fungal problems like various rots is necessary, especially in poorly drained soils or areas with high humidity. Occasionally, localized pest issues such as bagworms might appear, requiring targeted organic treatment if infestation is severe.
A major concern for gardeners is climate compatibility, as noted by its tendency to struggle in environmental conditions significantly different from its native habitat, such as the St. Louis area climate. If planted outside its preferred cool summer home, the tree may exhibit flagging or dieback, reflecting environmental stress rather than specific pest pressure. Proper watering—avoiding both drought and saturation—is the best preventative measure for general conifer health.
Frequently Asked Questions
What hardiness zones is Western red cedar suitable for?
The Thuja plicata ‘Aurea’ is best suited for USDA Hardiness Zones 5 through 7.
How large does Thuja plicata ‘Aurea’ grow?
This cultivar typically reaches a height between 40 and 50 feet, with a spread of 10 to 15 feet at maturity.
What sun exposure does Thuja plicata ‘Aurea’ need?
This needled evergreen performs best when situated in full sun to partial shade conditions.
When does Western red cedar bloom?
The Thuja plicata ‘Aurea’ is a conifer and is considered non-flowering.
Conclusion
The vibrant yellow summer color of Thuja plicata ‘Aurea’ offers a unique, warm contrast to traditional dark evergreens, making this Western red cedar cultivar highly valuable for structural interest and screening. Its aromatic foliage and robust form ensure year-round appeal in suitable climates. Before incorporating this striking conifer, confirm that your growing site provides the necessary medium moisture and falls within USDA Zones 5-7.
Companion Planting
Selecting appropriate neighbors ensures the Thuja plicata ‘Aurea’ thrives without competition for moisture or light that it dislikes. Given its preference for cool, moist, fertile soil, pair it with other moisture-loving conifers like Japanese Cedar (Cryptomeria japonica) or moisture-tolerant broadleaf evergreens such as Rhododendrons, provided they are situated where they don’t shade the base of the cedar too heavily. Avoid planting drought-tolerant Mediterranean herbs or species that require intense, dry heat, as cultural conflicts will lead to stress.
Seasonal Care Calendar
Spring is the ideal time for any needed structural pruning, though heavy pruning should be avoided on mature Western red cedar. Focus on applying a balanced, slow-release fertilizer around the drip line just as new growth begins, ensuring nutrients are available as the summer heat approaches. During the summer months, monitor water needs closely; if rain is scarce, supplemental, deep watering is essential to keep the soil consistently moist, preventing the stress that leads to browning or dieback in the foliage of Thuja plicata ‘Aurea’. Prepare for winter by ensuring the ground is well-watered before the first hard freeze, helping the roots manage dormancy without desiccation.
