Symphytum azureum

RHS Plant Profile

blue comfrey

Herbaceous Perennial

Buy this from Plant Nurseries
2 Suppliers

Vigorous, spreading, hairy perennial about 40-60cm tall, with pale to mid-green leaves up to 25cm long. One-sided sprays of hanging, tubular bright blue flowers appear in late spring and early summer

Position

Full sun, Partial shade

Soil Types

Chalk, Clay, Loam

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

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

Position

Full sun Partial shade

Aspect: East–facing or North–facing or 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): H7

Colour & Scent

Season	Stem	Flower	Foliage	Fruit
Spring
Summer
Autumn
Winter

Botanical Details

Family: Boraginaceae
Native to GB/Ireland: No
Foliage: Deciduous
Habit: Clump forming
Potentially harmful: Harmful if eaten repeatedly. Wear gloves and other protective equipment when handling Pets (rabbits, rodents): Harmful if eaten repeatedly - for further information and contact numbers regarding pets, see the HTA guide to potentially harmful plants
Genus: Symphytum are rhizomatous herbaceous perennials, sometimes invasive, with large leaves and nodding clusters of tubular flowers
Name Status: Unresolved

How to Grow

Cultivation

Grow in moderately fertile, moist soil in sun or partial shade. Be aware the plant growth can be vigorous once established and has the potential to become a nuisance, so may require appropriate management

Propagation

Propagate by division of fleshy roots in spring. Propagate by root cuttings in early winter. Propagate by seed sown in pots in a cold frame in autumn or spring

Suggested planting locations and garden types

Cottage and informal garden
Wildlife gardens
Ground cover

Pruning

Can be cut back after flowering to encourage neat, young foliage

Pests

Generally pest-free

Diseases

Generally disease-free