Ferula communis subsp. glauca

RHS Plant Profile
glaucous giant fennel

Synonyms

Ferula chiliantha

Plants for pollinators
Herbaceous Perennial

A robust perennial, 3-4m high in flower, forming a mound of aromatic, finely divided leaves that are bright green above and silvery beneath. Stout, branching grey-green stems, often flushed with purple, bear many rounded clusters of small yellow flowers in early to mid summer

Position

Full sun

Soil Types

Chalk, Loam, Sand

Max Height

2.5-4 metres

Max Spread

0.5-1 metres

Size

Time to Maturity
2–5 years
Max Spread
0.5-1 metres
Max Height
2.5-4 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
H3

Colour & Scent

Fragrance Foliage
Season Stem Flower Foliage Fruit
Spring
Summer
Autumn
Winter

Botanical Details

Family
Apiaceae
Native to GB/Ireland
No
Foliage
Deciduous
Habit
Columnar upright
Genus
Ferula are striking, large tap-rooted herbaceous perennials with big, pinnately divided leaves and compound umbels of small white, yellow or purple flowers; may die after flowering
Name Status
Correct
Plant Range
Med. to Arabian Pen.

How to Grow

Cultivation

Grow in fertile, well-drained soil in full sun; protect with a dry, bracken mulch in winter. May take some years to flower. Plants sometimes die after seeding

Propagation

Propagate by seed, sown in pots in a cold frame as soon as ripe. Prick out seedlings into deep pots to allow tap root to develop

Suggested planting locations and garden types

  • Architectural
  • Cottage and informal garden
  • Gravel garden
  • Mediterranean climate plants
  • Wildlife gardens

Pruning

To enhance foliage, remove flowering stems as soon as they appear, or after blooming if seed is not required

Pests

May be susceptible to aphids and slugs

Diseases

May be susceptible to downy mildews