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Phormium cookianum (Mountain flax)

Beginner
skill rating
1 hour care
per year
2m
Max height
3m
Max spread
5-10 years
To maturity

Plant details

Botanical name

Phormium cookianum

Other names

Mountain flax, Wharariki, Phormium colensoi, Mountain lily

Genus

Phormium Phormium

Species

P. cookianum - P. cookianum is a clump-forming, evergreen perennial with broad, linear, arching, light to yellow-green leaves and upright panicles of tubular, yellow-green flowers in summer.


Phormium cookianum is: Evergreen

Habit

Clump-forming

Flower

Yellow-green in Summer

Foliage

Light green, Yellow-green in All seasons

How to care

Watch out for

Specific pests

Phormium mealybug Phormium mealybug

Diseases

Generally disease free.

General care

Pruning

Remove spent flower stalks in autumn.

Propagation methods

Division


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Where to grow

Phormium cookianum (Mountain flax) will reach a height of 2m and a spread of 3m after 5-10 years.

Suggested uses

Architectural, Beds and borders, City, Cottage/Informal, Drought Tolerant, Instant, Low Maintenance, Sub-Tropical

Cultivation

Best grown in well-drained, fertile soil in full sun. In cold areas, protect from frost with a dry mulch in winter.

Soil type

Chalky, Clay, Loamy, Sandy (will tolerate most soil types)

Soil drainage

Well-drained, Moist but well-drained

Soil pH

Acid, Alkaline, Neutral

Light

Full Sun

Aspect

South

Exposure

Exposed, Sheltered

UK hardiness Note: We are working to update our ratings. Thanks for your patience.

Tender in frost (H3), Hardy (H4)

Companion plants

We do not currently have companion plants added for this plant.

Botanical name

Phormium cookianum

Other names

Mountain flax, Wharariki, Phormium colensoi, Mountain lily

Genus

Phormium Phormium

Species

P. cookianum - P. cookianum is a clump-forming, evergreen perennial with broad, linear, arching, light to yellow-green leaves and upright panicles of tubular, yellow-green flowers in summer.

Foliage

Evergreen

Habit

Clump-forming


Colour

Flower

Yellow-green in Summer

Foliage

Light green, Yellow-green in All seasons


How to care

Watch out for

Specific pests

Phormium mealybug

Diseases

Generally disease free.

General care

Pruning

Remove spent flower stalks in autumn.

Propagation methods

Division


Monthly care advice


Where to grow

Phormium cookianum (Mountain flax) will reach a height of 2m and a spread of 3m after 5-10 years.

Suggested uses

Architectural, Beds and borders, City, Cottage/Informal, Drought Tolerant, Instant, Low Maintenance, Sub-Tropical

Cultivation

Best grown in well-drained, fertile soil in full sun. In cold areas, protect from frost with a dry mulch in winter.

Soil type

Chalky, Clay, Loamy, Sandy (will tolerate most soil types)

Soil drainage

Well-drained, Moist but well-drained

Soil pH

Acid, Alkaline, Neutral

Light

Full Sun

Aspect

South

Exposure

Exposed, Sheltered

UK hardiness Note: We are working to update our ratings. Thanks for your patience.

Tender in frost (H3), Hardy (H4)

USDA zones

Zone 11, Zone 10, Zone 9, Zone 8

Defra's Risk register #1

Plant name

Phormium cookianum (Mountain flax)

Common pest name

Australian grapevine yellows; Australian lucerne yellows; Australian yellows of grapevine

Scientific pest name

Candidatus Phytoplasma australiense'

Type

Phytoplasma

Current status in UK

Absent

Likelihood to spread to UK (1 is very low - 5 is very high)

2

Impact (1 is very low - 5 is very high)

4

General biosecurity comments

Phytoplasma present in Australia and New Zealand which could be damaging to grapevine and strawberry production; in particular; if introduced to the UK. EU regulations help to mitigate the risk of entry.

About this section

Our plants are under greater threat than ever before. There is increasing movement of plants and other material traded from an increasing variety of sources. This increases the chances of exotic pests arriving with imported goods and travellers, as well as by natural means. Shoot is working with Defra to help members to do their part in preventing the introduction and spread of invasive risks.

Traveling or importing plants? Please read "Don't risk it" advice here

Suspected outbreak? Click here for contact details to report to the relevant authority.

Date updated: 7th March 2019 For more information visit: https://planthealthportal.defra.gov.uk/

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This plant likes... Garden match
Soil types: Chalky, Clay, Loamy, Sandy (will tolerate most soil types) Tell us...
Soil drainage: Well-drained, Moist but well-drained Tell us...
Soil pH: Acid, Alkaline, Neutral Tell us...
Light: Full Sun Tell us...
Aspect: South Tell us...
Exposure: Exposed, Sheltered Tell us...
Hardiness: Tender in frost (H3), Hardy (H4) Tell us...

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