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Allium giganteum (Giant allium)

Beginner
skill rating
2 hours care
per year
1.5m
Max height
0.5m
Max spread
2-5 years
To maturity

Plant details

Botanical name

Allium giganteum

Other names

Giant allium

Genus

Allium Allium

Species

A. giganteum - A. giganteum has spreading, strap-shaped basal leaves which die down before the flowers, and tall stems bearing round umbels of bright purple flowers in summer.


Allium giganteum is: Deciduous

Fragrance

Foliage has a nice fragrence

Habit

Erect

Awards

RHS AGM (Award of Garden Merit)

Flower

Purple in Summer

Foliage

Grey-green in Summer

How to care

Watch out for

Pests

Pest free, may suffer from slugs on new growth.

Onion rot , Downy mildew Onion rot , Downy mildew

General care

Pruning

No pruning required.

Propagation methods

Division, Seed


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Where to grow

Allium giganteum (Giant allium) will reach a height of 1.5m and a spread of 0.5m after 2-5 years.

Suggested uses

Architectural, Cottage/Informal, Flower Arranging, Beds and borders, Gravel

Cultivation

Grow in fertile, but well-drained soil. Add grit to clay soils to improve drainage.

Soil type

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

Soil drainage

Moist but well-drained, Well-drained

Soil pH

Acid, Alkaline, Neutral

Light

Full Sun

Aspect

South, East, West

Exposure

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

Allium giganteum

Other names

Giant allium

Genus

Allium Allium

Species

A. giganteum - A. giganteum has spreading, strap-shaped basal leaves which die down before the flowers, and tall stems bearing round umbels of bright purple flowers in summer.

Foliage

Deciduous

Fragrance

Foliage has a nice fragrence

Habit

Erect

Awards

RHS AGM (Award of Garden Merit)


Colour

Flower

Purple in Summer

Foliage

Grey-green in Summer


How to care

Watch out for

Pests

Pest free, may suffer from slugs on new growth.

Specific diseases

Onion rot , Downy mildew

General care

Pruning

No pruning required.

Propagation methods

Division, Seed


Monthly care advice


Where to grow

Allium giganteum (Giant allium) will reach a height of 1.5m and a spread of 0.5m after 2-5 years.

Suggested uses

Architectural, Cottage/Informal, Flower Arranging, Beds and borders, Gravel

Cultivation

Grow in fertile, but well-drained soil. Add grit to clay soils to improve drainage.

Soil type

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

Soil drainage

Moist but well-drained, Well-drained

Soil pH

Acid, Alkaline, Neutral

Light

Full Sun

Aspect

South, East, West

Exposure

Sheltered

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

Hardy (H4)

Defra's Risk register #1

Plant name

Allium giganteum (Giant allium)

Common pest name

allium leaf miner

Scientific pest name

Phytomyza gymnostoma

Type

Insect

Current status in UK

Present (Limited)

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

3

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

3

General biosecurity comments

Pest of Allium already present in UK and spreading; previous consultation supported awareness raising only; industry should prepare for the event of findings in commercial crops.

Defra's Risk register #2

Plant name

Allium giganteum (Giant allium)

Common pest name

Asain cotton leafworm; Cluster caterpillar; Fall armyworm; Rice cutworm; Taro caterpiller; Tobacco budworm; Tobacco caterpillar; Tobacco cutworm; Tobacco leaf caterpillar

Scientific pest name

Spodoptera litura

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

Regulated pest; frequently intercepted with occasional outbreaks which have been successfully eradicated in the UK.

Defra's Risk register #3

Plant name

Allium giganteum (Giant allium)

Common pest name

Nematode; common spiral; Spiral nematode; Steiners spiral nematode

Scientific pest name

Helicotylenchus dihystera

Type

Nematode

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

Nematode pest unlikely to be very damaging in its own right; but used as a an indicator species to assess compliance of soil requirements of imported plants to be kept under review in light of EFSA evaluation of soil requirements.

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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(14/05/2011)

(05/06/2013)

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

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