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Iris versicolor (Blue flag)

Beginner
skill rating
1 hour care
per year
1m
Max height
0.4m
Max spread
2-5 years
To maturity
Low
Toxicity

Plant details

Botanical name

Iris versicolor

Other names

Harlequin blueflag, Blue flag, Larer blue flag, American water iris, Iris versicolour

Genus

Iris Iris

Species

I. versicolor - I. versicolor is a herbaceous perennial for a pond margin or marsh area. It has clumps of slender, green, strap leaves and voilet-blue flowers with white markings that bloom in spring until summer.


Iris versicolor is: Deciduous

Habit

Compact, Erect

Toxicity

Ingestion may cause severe discomfort.

Flower

White, Violet, Blue in Spring; Violet, Blue, White in Summer

Foliage

Mid-green in Spring; Mid-green in Summer

How to care

Watch out for

Specific pests

Slugs , Snails Slugs , Snails

Diseases

Generally disease-free.

General care

Propagation methods

Division, Seed


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Where to grow

Iris versicolor (Blue flag) will reach a height of 1m and a spread of 0.4m after 2-5 years.

Suggested uses

Cottage/Informal, Flower Arranging, Beds and borders, Wallside and trellises, Coastal, City

Cultivation

Plant in moist soil up to 20 cm of water. Will not tolerate drying-out.

Soil type

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

Soil drainage

Boggy damp conditions, Moisture-retentive, Pond/In water

Soil pH

Alkaline, Neutral

Light

Full Sun

Aspect

South, East, West

Exposure

Exposed, Sheltered

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

Hardy (H4)

Companion plants

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

Botanical name

Iris versicolor

Other names

Harlequin blueflag, Blue flag, Larer blue flag, American water iris, Iris versicolour

Genus

Iris Iris

Species

I. versicolor - I. versicolor is a herbaceous perennial for a pond margin or marsh area. It has clumps of slender, green, strap leaves and voilet-blue flowers with white markings that bloom in spring until summer.

Native to

Canada, Central United States, Eastern United States

Foliage

Deciduous

Habit

Compact, Erect

Toxicity

Ingestion may cause severe discomfort.


Colour

Flower

White, Violet, Blue in Spring; Violet, Blue, White in Summer

Foliage

Mid-green in Spring; Mid-green in Summer


How to care

Watch out for

Specific pests

Slugs , Snails

Diseases

Generally disease-free.

General care

Propagation methods

Division, Seed


Monthly care advice


Where to grow

Iris versicolor (Blue flag) will reach a height of 1m and a spread of 0.4m after 2-5 years.

Suggested uses

Cottage/Informal, Flower Arranging, Beds and borders, Wallside and trellises, Coastal, City

Cultivation

Plant in moist soil up to 20 cm of water. Will not tolerate drying-out.

Soil type

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

Soil drainage

Boggy damp conditions, Moisture-retentive, Pond/In water

Soil pH

Alkaline, Neutral

Light

Full Sun

Aspect

South, East, West

Exposure

Exposed, Sheltered

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

Hardy (H4)

USDA zones

Zone 8, Zone 7, Zone 6, Zone 5, Zone 4, Zone 3, Zone 2

Defra's Risk register #1

Plant name

Iris versicolor (Blue flag)

Common pest name

Red rice root aphid; Rice root aphid

Scientific pest name

Rhopalosiphum rufiabdominalis

Type

Insect

Current status in UK

Absent

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

3

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

3

General biosecurity comments

Potentially significant glasshouse pest; growers should monitor for its presence. Routine aphid control should be effective in mitigating risk.

Defra's Risk register #2

Plant name

Iris versicolor (Blue flag)

Common pest name

common blossom thrips; cotton bud thrips; tomato thrips

Scientific pest name

Frankliniella schultzei

Type

Insect

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)

3

General biosecurity comments

Polyphagous glasshouse pest; present in many countries; single finding in UK.

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: Boggy damp conditions, Moisture-retentive, Pond/In water Tell us...
Soil pH: Alkaline, Neutral Tell us...
Light: Full Sun Tell us...
Aspect: South, East, West Tell us...
Exposure: Exposed, Sheltered Tell us...
Hardiness: Hardy (H4) Tell us...

DISCUSS THIS PLANT

When to cut back Iris versicolor

Hello, the leaves on my Iris are still green but are flopping over and looking untidy. Is it ok to cut them back now? Thank you, Jane read more

There are 2 active discussions about Iris versicolor (Blue flag)

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GARDENS WITH THIS PLANT

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Robert Kay
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Jane

ARTICLES WITH THIS PLANT

A revitalised Oxfordshire garden with the help of Mark Griffiths

My beautiful Oxfordshire garden was revitalised with the help of Mark Griffiths. Sheltered by old walls and high fences, the garden that surrounds my North Oxford home covers about 750 square metres. read more


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