Juniperus scopulorum ‘Moonglow’

Description

Quick Facts

• Botanical name: Juniperus scopulorum ‘Moonglow’
• Common name: Rocky Mountain juniper
• Type: Evergreen coniferous tree / large shrub
• Mature height and spread: Around 4–6m tall and 1.5–2m wide at maturity, which takes 15–20 years or more. Moderate growth.
• Flowering period and colour: Insignificant. Conifers carry small cones, not showy flowers.
• Foliage: Dense, scale-like foliage in silvery-blue, held on an upright, narrow pyramidal form. Colour is strongest in full sun.
• Hardiness: Fully hardy in Ireland and the UK (around RHS H7, to about -20°C).
• Soil: Well-drained soil, including poor, sandy or chalky ground. Dislikes waterlogging.
• Aspect: Full sun for the best colour and density.
• Maintenance: Low.

Description

A smart, upright juniper with a naturally narrow, pyramidal shape and silvery-blue foliage that keeps its colour all year. It stays neat with little attention and has a tidy, formal look, so it suits small gardens, driveways and entrances. It’s a handy evergreen for screening or structure, and works well in pairs or in a row.

Caragh Garden Notebook

Planting Plant in autumn or spring in full sun and free-draining soil. Dig a hole about twice the width of the pot, keep the rootball level with the surface, firm in gently and water well. Allow 1–1.5m between plants for a screen. On heavy clay, improve the drainage or plant on a slight mound.

Watering Water regularly through the first season to establish a good root system. Once settled it is fairly drought tolerant. Avoid constantly wet soil.

Feeding Little feeding is needed. A slow-release conifer fertiliser in spring suits pots and poor soils.

Seasonal Care and Tidy-Up Spring: Check for winter damage and trim lightly if needed. Summer: Keep container plants watered. Autumn: Brush fallen debris off the base. Winter: In heavy snow, gently shake the branches to prevent bending or splaying.

Division Not applicable. Pruning is minimal. Trim lightly in spring or late summer only if needed, cutting back to green growth. Junipers don’t reliably regrow from bare, brown wood, so never cut into it.

Pests and Problems

• Tip blight (phomopsis or kabatina): A fungal disease that browns shoot tips, mainly in damp conditions. Remove affected tips, improve airflow, and avoid overhead watering.
• Juniper scale and aphids: Small sap-feeding insects that cause yellowing patches. Check regularly.
• Rust diseases: Some juniper species can host rust fungi that alternate with other plants such as pears, hawthorn and apples. The impact varies by species and is generally minor in home gardens. If you have fruit trees nearby, keep an eye out for orange spots on the leaves.
• Handling: The foliage and sap can irritate sensitive skin, so wear gloves and long sleeves when planting and pruning.

Design Notes Perfect as a formal accent in pairs by a door or gate, or planted in a line for screening. Its silvery-blue colour pairs well with purple foliage, roses, lavender and grasses, and contrasts nicely with dark evergreens. It also works well in large pots.

Propagation Nurseries propagate named junipers by cuttings or grafting, usually in late summer to autumn. This is slow and unreliable for home gardeners. Seed won’t reliably produce the same tree.