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BeddingConservatory GreenhouseHerbaceous PerennialAnnual Biennial

Trachelium caeruleum

blue throatwort

An erect perennial to 90cm, usually grown as an annual, with lance-shaped leaves and small, slightly fragrant, violet-blue flowers in domed clusters to 15cm across in summer

Other common names

throatwort

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Ultimate height

0.5–1 metres

Time to ultimate height

1–2 years

Ultimate spread

0.1–0.5 metres

Loam

Sand

Moisture

Moist but well–drained

pH

Acid, Alkaline, Neutral

	Stem	Flower	Foliage	Fruit
Spring
Summer
Autumn
Winter

Full sun

Aspect

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)

Botanical details

Family: Campanulaceae
Native to GB / Ireland: No
Foliage: Deciduous
Habit: Bushy
Genus: Trachelium can be cushion-forming or erect perennials with small, simple leaves and tubular flowers with 5 spreading lobes, in summer
Name status: Correct
Plant range: W Mediterranean

How to grow

Cultivation

Grow in moderately fertile, well-drained soil in full sun, ideally with some midday sun. Water freely in dry weather

Propagation

Propagate by seed sown at 16°C in spring

Suggested planting locations and garden types

City and courtyard gardens
Patio and container plants
Cottage and informal garden
Flower borders and beds
Cut flowers
Wall side borders

Pruning

Cut back after flowering

Pests

Generally pest-free

Diseases

Generally disease-free

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