Paeonia (Gansu Group) 'Highdown' (S)

RHS / Joanna Kossak

Synonyms

Paeonia × suffruticosa 'Highdown'
Paeonia rockii 'Joseph Rock'
Paeonia 'Joseph Rock' not Klehm
Paeonia rockii 'Rock's Variety'
Paeonia × suffruticosa 'Joseph Rock'
Paeonia × suffruticosa Rock's form
Paeonia rockii misapplied
Paeonia rockii hybrid

Shrubs

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A large, deciduous perennial shrub with an interesting history (see article on RHS website). It has dark green, hairy leaves and very large and showy rose-scented pale purple flowers with dark purple markings in the centre, which age to white, appearing in the summer

Position

Full sun, Partial shade

Soil Types

Clay, Loam, Sand

Max Height

1.5-2.5 metres

Max Spread

1.5-2.5 metres

Size

Time to Maturity: 5–10 years
Max Spread: 1.5-2.5 metres
Max Height: 1.5-2.5 metres

Growing Conditions

Clay Loam Sand

Moisture: Well–drained
pH: Acid or Alkaline or Neutral

Position

Full sun Partial shade

Aspect: 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): H6

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

Best grown in neutral, humus rich soils, but slightly acid or slightly alkaline soils are tolerated. Good drainage is essential. Ideally, plant in a sunny position. Can be grown in light shade, but the plants may become straggly. Fully hardy, but young foliage and flowers can be damaged by late frost. See tree peony cultivation for further information

Propagation

Propagate by seed, seeds are doubly dormant needing two winters to germinate. There is a good chance that the young plants will be true to type or similar. Propagate by grafting, from semi-ripe cutting or try layering

Suggested planting locations and garden types

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

Pruning

Pruning group 1

Pests

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

Diseases

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