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Bulbs

Allium rosenorum 'Michael H. Hoog'

allium 'Michael H. Hoog'

Bulbous perennial with narrow, strap-shaped mid-green leaves that fade as flowering begins, and flower stems reaching to 1m tall bearing large umbels, up to 15cm wide, of purple-violet flowers in late spring and early summer

Synonyms

Allium jesdianum 'Michael Hoog'
Allium rosenbachianum 'Michael Hoog'

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Ultimate height

1–1.5 metres

Time to ultimate height

1–2 years

Ultimate spread

0.1–0.5 metres

Chalk

Loam

Sand

Moisture

Moist but well–drained, Well–drained

pH

Acid, Alkaline, Neutral

	Stem	Flower	Foliage	Fruit
Spring
Summer
Autumn
Winter

Full sun

Aspect

South–facing or West–facing

Exposure

Sheltered

Hardiness
Hardiness ratings
All ratings refer to the UK growing conditions unless otherwise stated. Minimum temperature ranges (in degrees C) are shown in brackets
H1a: under glass all year (>15C)
H1b: can be grown outside in the summer (10 - 15)
H1c: can be grown outside in the summer (5 - 10)
H2: tolerant of low temperatures, but not surviving being frozen (1 to 5)
H3: hardy in coastal and relatively mild parts of the UK (-5 to 1)
H4: hardy through most of the UK (-10 to -5)
H5: hardy in most places throughout the UK even in severe winters (-15 to -10)
H6: hardy in all of UK and northern Europe (-20 to -15)
H7: hardy in the severest European continental climates (< -20)

Botanical details

Family: Amaryllidaceae
Native to GB / Ireland: No
Foliage: Deciduous
Habit: Clump forming
Potentially harmful: Bulbs may cause skin irritation. Wear gloves and other protective equipment when handling
Genus: Allium are bulbous herbaceous perennials with a strong onion or garlic scent, linear, strap-shaped or cylindrical basal leaves and star-shaped or bell-shaped flowers in an umbel on a leafless stem
Name status: Accepted

How to grow

Cultivation

Grow in full sun and fertile well-drained soil. It is best to grow in containers where garden soil is heavy clay and prone to saturation over winter. See allium cultivation

Propagation

Propagate by offsets which can be carefully detached by lifting the bulb after flowering has finished. See bulb propagation

Suggested planting locations and garden types

Cottage and informal garden
City and courtyard gardens
Gravel garden
Wildlife gardens
Flower borders and beds
Cut flowers

Pruning

No pruning required, other than to remove old flowered stems and foliage

Pests

May be susceptible to allium leaf miner and onion fly

Diseases

May be susceptible to onion white rot, and onion downy mildew

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