Paeonia 'Boreas' (S)

Shrubs

A clump-forming, deciduous herbaceous perennial to around 120cm with mid-green foliage. Semi-double, velvety, fragrant dark raspberry-red flowers with ruffled, asymmetrical petals appear in late spring to early summer

Position

Full sun, Partial shade

Soil Types

Chalk, Clay, Loam, Sand

Max Height

1-1.5 metres

Max Spread

1-1.5 metres

Size

Time to Maturity: 5–10 years
Max Spread: 1-1.5 metres
Max Height: 1-1.5 metres

Growing Conditions

Chalk Clay Loam Sand

Moisture: Moist but well–drained
pH: Acid or Alkaline or Neutral

Position

Full sun Partial shade

Aspect: East–facing or South–facing or West–facing
Exposure: Sheltered
Hardiness

Hardiness Ratings

All ratings refer to the UK growing conditions unless otherwise stated. Minimum temperature ranges (in degrees C) are shown in brackets

H1A: under glass all year (>15C)
H1B: can be grown outside in the summer (10 - 15)
H1C: can be grown outside in the summer (5 - 10)
H2: tolerant of low temperatures, but not surviving being frozen (1 to 5)
H3: hardy in coastal and relatively mild parts of the UK (-5 to 1)
H4: hardy through most of the UK (-10 to -5)
H5: hardy in most places throughout the UK even in severe winters (-15 to -10)
H6: hardy in all of UK and northern Europe (-20 to -15)
H7: hardy in the severest European continental climates (< -20): H5

Colour & Scent

Fragrance Flower

Season	Stem	Flower	Foliage	Fruit
Spring
Summer
Autumn
Winter

Botanical Details

Family: Paeoniaceae
Native to GB/Ireland: No
Foliage: Deciduous
Habit: Bushy
Potentially harmful: Pets (dogs, cats): Skin irritant. For further information and contact numbers regarding pets, see the HTA guide to potentially harmful plants
Genus: Paeonia may be herbaceous perennials or deciduous sub-shrubs with large, divided leaves and showy large bowl-shaped flowers, usually in early summer
Name Status: Accepted
Horticultural Group

Horticultural Classification Codes

Horticultural Classification Codes are often given to genera which have a large number of species or cultivars. They are used to categorise cultivated plants based on specific, shared characteristics such as shape, colour, size or flowering time, and can be displayed as letters or numbers

For example:
Dahlia ‘Sunset Kate (Sin) = Single flower
Rosa ‘Marigold’ (HT) = Hybrid Tea: Shrubby peonies are sparsely branched deciduous shrubs leaves divided into several finger-like lobes, and bowl-shaped flowers in late spring or early summer

How to Grow

Cultivation

Will grow well in fertile, humus-rich, moist but well-drained soil in full sun or partial shade in a sheltered position. Plant in autumn, add fertiliser in spring to promote good growth and mulch avoiding the stem area. Irrigate regularly until the plant becomes established after which it should not require routine watering. See tree peony cultivation for more details.

Propagation

Propagate by grafting, from a semi-ripe cutting or layering

Suggested planting locations and garden types

City and courtyard gardens
Cottage and informal garden
Flower borders and beds

Pruning

Prune dead stems to a healthy bud in late winter and cut flowered shoots just above the new growth in summer or autumn. Cut stems by a third in autumn to encourage vigor if the plant becomes leggy. See Pruning group 1 for more details.

Pests

May be susceptible to leaf and bud eelworm and soil-dwelling swift moth caterpillar

Diseases

May be susceptible to a virus, honey fungus, Verticillium wilt, peony leaf blotch and peony wilt