Eryngium planum 'Tetra Petra'
blue eryngo 'Tetra Petra'
A robust, clump-forming perennial with erect branched stems and spiny, highly divided dark green leaves. Flowering in summer, it has abundant small thimble shaped flower-heads with spiky silvery-blue bracts which can also be very attractive if left on the plant after the flowering period
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Size
Ultimate height
0.5–1 metresTime to ultimate height
2–5 yearsUltimate spread
0.1–0.5 metresGrowing conditions
Moisture
Well–drainedpH
Acid, Alkaline, NeutralColour & scent
Stem | Flower | Foliage | Fruit | |
Spring | Green | |||
---|---|---|---|---|
Summer | Blue Grey Silver | Green | ||
Autumn | Green | |||
Winter |
Position
- Full sun
Aspect
East–facing or South–facing or West–facing
Exposure
Exposed or ShelteredDrought resistance
Yes Hardiness
H5Botanical details
- Family
- Apiaceae
- Native to the UK
- No
- Foliage
- Deciduous
- Habit
- Clump forming
- Genus
Eryngium can be annuals, biennials or perennials with simple or divided leaves, often spiny edged, and cone-like flower-heads often surrounded by an involucre of conspicuous spiny bracts
- Name status
Unresolved
How to grow
Cultivation
Will grow well in poor, moderately fertile, well-drained soil in full sun avoiding wet winter conditions
Propagation
Propagate by seed, by root cuttings in late winter and by division in spring
Suggested planting locations and garden types
- Architectural
- City and courtyard gardens
- Cottage and informal garden
- Gravel garden
- Wildlife gardens
- Coastal
- Cut flowers
- Flower borders and beds
Pruning
Cut back any dead foliage throughout the season and but leave spent flowers for winter interest. Cut flowers before they open for floristry purposes
Pests
May be susceptible to leaf and bud eelworms, and slugs and snails
Diseases
May be susceptible to root rot and powdery mildews
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