Lavandula × intermedia 'Sumian'

RHS Plant Profile
lavender 'Sumian'

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Shrubs

A bushy, evergreen shrub to around 30cm in height, with linear, aromatic silvery-grey leaves. Spikes of soft, dark violet-blue flowers appear on slender stems from late spring or early summer until the first frosts. A French cultivar with a high oil content

Position

Full sun

Soil Types

Chalk, Loam, Sand

Max Height

0.1-0.5 metres

Max Spread

1-1.5 metres

Size

Time to Maturity
2–5 years
Max Spread
1-1.5 metres
Max Height
0.1-0.5 metres

Growing Conditions

Chalk Loam Sand
Moisture
Well–drained
pH
Acid or Alkaline or Neutral

Position

Full sun
Aspect
South–facing or West–facing
Exposure
Exposed or 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
Drought Resistance
Yes

Colour & Scent

Fragrance Flower Foliage
Season Stem Flower Foliage Fruit
Spring
Summer
Autumn
Winter

Botanical Details

Family
Lamiaceae
Native to GB/Ireland
No
Foliage
Evergreen
Habit
Bushy
Genus
Lavandula are small aromatic evergreen shrubs with usually narrow, simple, entire, toothed or lobed leaves and small tubular flowers in dense spikes in summer
Name Status
Accepted

How to Grow

Cultivation

Grow in full sun in well-drained soil; will not tolerate waterlogging. See lavender cultivation for more advice

Propagation

Propagate by semi-hardwood cuttings in summer. See our video how to take lavender cuttings for more advice

Suggested planting locations and garden types

  • City and courtyard gardens
  • Cottage and informal garden
  • Gravel garden
  • Patio and container plants
  • Wildlife gardens
  • Banks and slopes
  • Cut flowers
  • Flower borders and beds

Pruning

pruning group 10; deadhead after flowering and trim foliage in spring. Avoid cutting back into old wood

Pests

May be susceptible to rosemary beetle and Spittlebugs

Diseases

May be susceptible to grey moulds (Botrytis) and honey fungus (rarely)