Primula japonica 'Millar's Crimson' (Japanese Primrose) — Rosette-forming, clump-forming

Overview

Primula japonica 'Millar's Crimson' is a rosette-forming, clump-forming perennial in the genus Primula, part of the Primulaceae family, with deciduous, semi-evergreen or evergreen; rosettes of crinkled or mealy leaves foliage. Primula japonica 'Millar's Crimson' grows best in partial shade; alpines and auriculas take more sun, and tolerates fertile humus-rich loam; alpine kinds need gritty free-draining soil soils and neutral to slightly acid; asiatic species dislike lime pH. Its UK hardiness is rated H4-H7 depending on group. Suggested uses include bog gardens, streamside planting and woodland gardens. It is native to Japan.

About

Primula japonica 'Millar's Crimson' is a rosette-forming, clump-forming perennial from the Primulaceae that suits damp, shaded spots. It produces a spring display from February to June and carries crinkled or mealy leaves in compact rosettes. Plant where soil remains reliably moist and where north, east or west aspects provide shelter.

Wikipedia contributors, CC BY-SA 4.0 — Primula japonica

About the genus

Primula is a genus of herbaceous flowering plants in the family Primulaceae. They include the primrose, a familiar wildflower of banks and verges. Other common species are P.

Wikipedia contributors, "Primula", CC BY-SA 4.0 — Primula

In the garden

Primula japonica 'Millar's Crimson' is a cultivar of Japanese primrose, a perennial native to Japan, grown for its spring flowering display. It forms clumps of crinkled or mealy leaves in rosettes and flowers in the UK between February and June. As a member of the Primulaceae it prefers part shade and a sheltered position rather than full sun. Give it a fertile, humus-rich loam with a neutral to slightly acidic pH; Asiatic primulas generally dislike lime. Soil moisture is a key factor: woodland and candelabra types need reliably moist ground, while the alpine relatives require much sharper drainage. Position plants on north, east or west-facing banks or beds where irrigation or consistent moisture is available. Hardiness varies across cultivated groups (H4–H7), which in practical terms means many forms tolerate typical UK winters from average to fully hardy depending on the clone. Use Primula japonica 'Millar's Crimson' at pond edges, in bog gardens or beneath trees in a woodland-planted border where the rosettes can form clumps and the spring flowers can be seen at close quarters. Planting in groups at a streamside margin makes the seasonal flush of flowers easy to admire from a path.

Growing conditions

Best soil and position for Primula

Sunlight: Partial shade; alpines and auriculas take more sun
Soil type: Fertile humus-rich loam; alpine kinds need gritty free-draining soil
Soil pH: Neutral to slightly acid; Asiatic species dislike lime
Soil moisture: Reliably moist for candelabra and woodland kinds; sharply drained for alpines
Aspect: North, east or west facing
Exposure: Sheltered
UK hardiness: H4-H7 depending on group

Plant details

Primula japonica 'Millar's Crimson' size, habit and characteristics

Plant type: Perennial
Habit: Rosette-forming, clump-forming
Foliage: Deciduous, semi-evergreen or evergreen; rosettes of crinkled or mealy leaves
Suggested uses: bog gardens, streamside planting, woodland gardens
Native to: Japan

Care notes

Pruning and caring for Primula japonica 'Millar's Crimson'

Cultivation: Match the group to the site and these are easy plants; ignore the distinction and they are short-lived. Candelabra and sikkimensis types want ground that never dries, so a streamside or bog garden suits them perfectly, while auriculas and the alpine species need gritty compost, protection from winter rain, and are traditionally grown in pots in an open frame. Woodland primulas ask for nothing more than leaf mould and dappled shade.
Pruning: No pruning required. Deadhead to prevent self-seeding where it is not wanted, and remove dead outer leaves from the rosettes to reduce rot.
Propagation: Divide after flowering, ideally every second or third year, as congested rosettes decline. Seed germinates best sown fresh and given a cold period, and many species self-sow freely.
Pest resistance: Vine weevil is the principal enemy, especially in pots, along with slugs, aphids and red spider mite under glass.
Disease resistance: Prone to grey mould and crown rot in stagnant damp. Primula brown core, a root rot, causes gradual decline in long-established plantings.

Frequently asked questions

How do I grow Primula japonica 'Millar's Crimson'?

Match the group to the site and these are easy plants; ignore the distinction and they are short-lived. Candelabra and sikkimensis types want ground that never dries, so a streamside or bog garden suits them perfectly, while auriculas and the alpine species need gritty compost, protection from winter rain, and are traditionally grown in pots in an open frame. Woodland primulas ask for nothing more than leaf mould and dappled shade.

Where is the best place to plant Primula japonica 'Millar's Crimson'?

Primula japonica 'Millar's Crimson' prefers partial shade; alpines and auriculas take more sun. It suits sheltered positions.

What soil does Primula japonica 'Millar's Crimson' need?

Primula japonica 'Millar's Crimson' grows best in fertile humus-rich loam; alpine kinds need gritty free-draining soil soil. It prefers neutral to slightly acid; asiatic species dislike lime soil. Aim for soil that stays reliably moist for candelabra and woodland kinds; sharply drained for alpines.

How do I prune Primula japonica 'Millar's Crimson'?

No pruning required. Deadhead to prevent self-seeding where it is not wanted, and remove dead outer leaves from the rosettes to reduce rot.

Is Primula japonica 'Millar's Crimson' hardy in the UK?

Primula japonica 'Millar's Crimson' has an RHS hardiness rating of H4, meaning it is hardy through an average UK winter, tolerating -10 to -5°C.

How do I propagate Primula japonica 'Millar's Crimson'?

Divide after flowering, ideally every second or third year, as congested rosettes decline. Seed germinates best sown fresh and given a cold period, and many species self-sow freely.

More in the Primula genus

Browse all Primula →