Southern White Cedar ‘Blue Rock’ 20/40cm (2L)

Southern White Cedar ‘Blue Rock’ – Chamaecyparis thyoides is a compact, slow-growing conifer that brings year-round colour and texture to gardens. This American native cultivar forms a neat, pyramidal shape with distinctive blue-grey foliage that takes on attractive purple-bronze tones during winter months. The fine, scale-like leaves create a soft, feathery appearance that contrasts beautifully with broader-leaved plants and other conifers.

This 20/40cm specimen in a 2-litre pot is ideal for establishing in borders, rockeries, or containers. ‘Blue Rock’ maintains a naturally compact habit without requiring extensive pruning, making it perfect for smaller gardens where space is at a premium. The cultivar’s moderate growth rate allows you to enjoy its development over many years whilst keeping maintenance to a minimum.

The blue-grey summer foliage provides excellent contrast in mixed plantings, working particularly well alongside ornamental grasses, heathers, and other dwarf conifers. As temperatures drop in autumn and winter, the foliage transforms to display rich purple and bronze hues, ensuring the plant remains a focal point throughout the year. This seasonal colour change adds valuable winter interest when many other plants have finished their display.

Southern White Cedar ‘Blue Rock’ thrives in moist, acidic soils and appreciates a position with good drainage. Unlike many conifers that prefer drier conditions, this species naturally grows in boggy areas in its native habitat, making it an excellent choice for damper parts of the garden where other evergreens might struggle. The plant’s tolerance of wet conditions makes it particularly suitable for clay soils that retain moisture.

This cultivar works well in foundation plantings, as a specimen plant, or grouped with other dwarf conifers to create textural interest. Its compact size and slow growth make it suitable for long-term container cultivation, where it can provide structure on patios and terraces. The pyramidal form adds vertical interest without overwhelming surrounding plants.

Care Guide

Plant in moist, acidic to neutral soil with good drainage. Choose a position in full sun or partial shade, though the best foliage colour develops with adequate sunlight. Water regularly during the first growing season to establish a strong root system, and continue watering during dry spells, particularly in summer.

Apply a layer of organic mulch around the base to retain moisture and suppress weeds, keeping it clear of the stem. Feed in spring with an ericaceous fertiliser to maintain healthy growth and foliage colour. The naturally acidic feed suits this species perfectly and helps prevent nutrient deficiencies.

Pruning is rarely necessary as ‘Blue Rock’ maintains its compact shape naturally. Remove any dead or damaged branches in spring if required. The plant is generally pest and disease resistant, though it may occasionally suffer from root rot in poorly drained soils. Ensure adequate drainage when planting to prevent waterlogging around the roots.

Protect young plants from harsh winter winds in exposed locations, though established specimens are remarkably hardy. Container-grown plants may need additional watering during winter dry spells and benefit from occasional feeding during the growing season.

Ultimate height
4–8 metres

Time to ultimate height
20–50 years

Ultimate spread
1.5–2.5 metres