Golden Japanese sweet flag

Perennial

Acorus gramineus 'Ogon'

Golden Japanese sweet flag

Also known as: Acorus gramineus 'Oborozuki' (misapplied)

A low, grass-like evergreen with bright gold and green striped foliage for pond edges and moist ground.

  • Full sun, Partial shade
  • 20–30 cm (8–12 in)
  • 20–30 cm (8–12 in)
  • H5 · Zone 6
  • May–June
  • Semi evergreen

Overview

This slender sweet flag forms neat, arching tufts of narrow, glossy leaves striped gold and green, holding their colour through winter and brightening damp shade. It is a true moisture lover, equally happy in permanently wet soil, a shallow pond basket or the margins of a bog garden, and only needs dividing occasionally to keep clumps from becoming congested.

At a Glance

Sun Full sun, Partial shade
Height 20–30 cm (8–12 in)
Spread 20–30 cm (8–12 in)
Hardiness H5 · Zone 6
Flowers May–June
Soil Clay, Loam
Moisture Wet
Habit Clump forming, Tufted
Water High
Maintenance Easy

Growing Conditions

Min. Temperature -15°C (5°F)
pH Range 5.5–7.5
Fertility Fertile
Drainage Poorly Drained

Aspect Suitability

  • East-facing
  • South-facing
  • West-facing

Site Tolerance

  • Wet soil

Soil Tolerance

  • Clay
  • Loam
  • Acid
  • Neutral pH
  • Alkaline

Foliage

Persistence Semi evergreen
Colour Gold, Green
Leaf shape / texture linear
  • Variegated

Foliage interest: 12 months of the year

Seasonal Timeline

Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec
Flowering
Foliage
Propagate
  • Flowering May Jun
  • Foliage 12 months of the year
  • Propagate Mar Apr

Maintenance Calendar

  • Mar Divide congested clumps as growth resumes
  • Apr Plant out or reposition divisions into permanently moist soil
  • Jun Ensure the root area never dries out through summer
  • Sep Remove any tatty or browned leaf tips
  • Nov Check water levels stay adequate for basket-grown plants

Garden Design

Works well in: Bog, Contemporary, Cottage, Pondside

Use to edge a pond or line a damp path where the gold striping catches the light; it also does well in a shallow aquatic basket if the crown stays just above water level.

Companion planting: Irises, Primulas, Moisture-loving ferns

Wildlife Value

  • Shelter

Safety

No well-established toxicity; ornamental foliage only.