Acorus gramineus 'Ōgon' (v)

RHS Plant Profile

slender sweet flag 'Ōgon'

Synonyms

Agrostis gramineus 'Ogon'
Acorus gramineus 'Oborozuki' misapplied

Herbaceous Perennial Aquatic Bogs Grass Like

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A compact, semi-evergreen marginal aquatic perennial, forming a clump to 30cm tall, with narrow, bright yellow leaves, lightly striped with yellowish-green

Position

Full sun

Soil Types

Chalk, Clay, Loam

Max Height

0.1-0.5 metres

Max Spread

0.1-0.5 metres

Size

Time to Maturity: 5–10 years
Max Spread: 0.1-0.5 metres
Max Height: 0.1-0.5 metres

Growing Conditions

Chalk Clay Loam

Moisture: Poorly–drained
pH: Acid or Alkaline or Neutral

Position

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): H6

Colour & Scent

Season	Stem	Flower	Foliage	Fruit
Spring
Summer
Autumn
Winter

Botanical Details

Family: Acoraceae
Native to GB/Ireland: No
Foliage: Semi evergreen
Habit: Clump forming
Genus: Acorus are deciduous or semi-evergreen, moisture-loving rhizomatous perennials forming tufts of linear or sword-shaped leaves, with insignificant spike-like flowers borne near the tips of central leaf-like stems
Name Status: Accepted

How to Grow

Cultivation

Easy to grow in wet or very moist fertile soils. Can be planted in baskets in shallow water. It also makes a useful aquarium plant but is short-lived where water temperatures exceed 22°C for long periods. Divide every few years to prevent congestion. See pond plants and bog gardens for further advice

Propagation

Propagate by rhizome division at the beginning of the growing season. Pot up and plant out only when fully established

Suggested planting locations and garden types

Cottage and informal garden
Low Maintenance

Pruning

Tidy old or damaged foliage in early spring if necessary

Pests

Generally pest-free

Diseases

Generally disease-free