Rosmarinus officinalis 'Severn Sea'

RHS Plant Profile
rosemary 'Severn Sea'

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rosemary 'Severn Sea' RHS

Synonyms

Rosmarinus officinalis 'Severn Sea', Rosmarinus 'Seven Sea'

RHS Recommended

Plants for pollinators
Herbs - Culinary Shrubs
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Spreading evergreen shrub about 1m in height, with arching branches bearing aromatic, linear, dark green leaves, and bright blue, two-lipped flowers in axillary clusters in spring and summer, sometimes again in autumn

Position

Full sun

Soil Types

Chalk, Clay, Loam, Sand

Max Height

0.5-1 metres

Max Spread

0.5-1 metres

Size

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

Growing Conditions

Chalk Clay Loam Sand
Moisture
Moist but well–drained or Well–drained
pH
Acid or Alkaline or Neutral

Position

Full sun
Aspect
South–facing or West–facing or East–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)
H4

RHS Recommended: for People & Planet

RHS Recommended Plants for People & Planet

For Water Resilience

Plants for Flood Resilience

Plants that can help manage heavy rain by catching rainfall, slowing surface run-off, encouraging water into the soil or taking it up through their roots, contributing to flood resilient gardens.

Plants for both Wet and Dry Conditions

Plants that cope with changing soil moisture, including wet winters and extended summer dry. Once established, they grow as wet and dry conditions alternate.

For Temperature Resilience

Plants for Temperature Cooling

Plants that cool air temperature by providing shade, transpiration, or reflection to reduce heat impact on people, animals, soil or other ground surface.

Plants for Wind Shelter

Plants with dense canopies often grown as a tall thick hedge or grouping can block wind and shelter gardens, buildings and people.

For Carbon Storage

Plants for Carbon Storage

Plants that can take up carbon (CO₂) through photosynthesis and store it within the plant or deposit it by their roots into the soil.

For Biodiversity

Plants for Pollinators

Plants that have flowering properties (pollen and/or nectar) that are particularly beneficial for pollinating insects such as bees, butterflies and hoverflies.

Growing conditions for maximum benefit

This plant will provide the maximum benefits if it is healthy and allowed to grow to maturity

For Bio-Diversity

  • Plants for Pollinators

Colour & Scent

Fragrance Foliage
Season Stem Flower Foliage Fruit
Spring
Summer
Autumn
Winter

Botanical Details

Family
Lamiaceae
Native to GB/Ireland
No
Foliage
Evergreen
Habit
Bushy
Potentially harmful
Skin allergen. Wear gloves and other protective equipment when handling
Genus
Salvia can be annuals, biennials, herbaceous or evergreen perennials, or shrubs. They have paired, simple or pinnately lobed, often aromatic leaves and 2-lipped flowers in whorls, forming simple or branched spikes or racemes
Name Status
Synonym
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

This genus has changed from Rosmarinus to Salvia

How to Grow

Cultivation

Easy to grow aromatic, evergreen shrub. Prefers poor, well-drained soil and may be used as a formal or informal low hedge which should be trimmed after flowering. See rosemary cultivation for further advice

Propagation

Propagate by semi-hardwood cuttings

Suggested planting locations and garden types

  • City and courtyard gardens
  • Coastal
  • Cottage and informal garden
  • Gravel garden
  • Mediterranean climate plants
  • Patio and container plants
  • Wildlife gardens
  • Flower borders and beds

Pruning

pruning group 9

Pests

May be susceptible to rosemary beetle, cuckoo spit, sage leafhopper, tortrix moth and scale insects

Diseases

May be susceptible to honey fungus (rarely), Powdery mildews, Verticillium wilt and foot and root rots