Japanese forest grass
Hakonechloa macra · Poaceae Popular
The plain green species: a cascading mound of bright green, bamboo-like leaves that all flow in one direction, like water over a stone. It turns orange and bronze in autumn.
- Size
- 18 in tall, 24 in wide
- Zones
- 5 to 9
- Light
- Part sun to shade
- Flowers
- Grown for its leaves
- Pets
- No toxicity recorded
- Job in a bed
- Edging
A bed built around Japanese forest grass
The planner designed this bed around Japanese forest grass when this page was made: a 12 × 6 ft (3.7 × 1.8 m) naturalistic planting in zone 6, part shade. It chose the other plants from the 513 that suit those conditions, and says below why Japanese forest grass stands where it does.
The plants
- 1 Japanese forest grass × 3, green leaves
- 2 Woodland strawberry × 9, white
- 3 Leadwort × 8, blue
- 4 Solomon's seal × 5, white
- 5 Tall astilbe 'Superba' × 3, purple
- 6 White bleeding heart × 1, white
- 7 Hardy cyclamen × 10, pink
- 8 Yellow trout lily × 5, yellow
Why this plant
- The only plant grown for its leaves. Leaf lasts all season, where a flower lasts a few weeks.
- The bed's only structure. Shrubs and grasses keep their shape when the perennials die down, and it is the only one here.
- Part of the matrix. The low fabric of grasses and groundcovers that the taller plants come up through.
Why here
- In the middle. At 18 in it is the step between leadwort (10 in) in front and tall astilbe 'Superba' (4 ft) behind: each is seen over the one before.
- 3 plants in one group. Massed, one kind reads as a single shape. Scattered, it would look spotty.
Why now
- Here for its leaves, spring to frost. They cover the 12 weeks between early March and late November when nothing on the plan is in flower.
- Stands through winter. Left uncut, it holds its shape until March, when the perennials have gone.
Planned as a naturalistic planting: low grasses and groundcovers, the matrix, make up 47% of the planted ground. Something is in flower for 28 weeks, from mid April to mid October. Tall astilbe 'Superba' and Solomon's seal anchor the back corners of the bed: the tallest plants on the plan stand there.
The planner's own design check: 12 Excellent, 5 Good. It flags one thing to watch: Nothing on this plan is highly poisonous or an aggressive spreader.
Open this bed in the planner Change its size, the sun or the style, move plants about, or swap one for another.
Where Japanese forest grass goes in a border
At 18 in it belongs at the front of a bed. In the planner's ten height classes it is short (12 to 18 in).
Its job: edging. A low, neat plant used in short runs of three or five along the front to finish the edge (or, in a formal bed, in one even row).
The green form is stronger and takes more sun than the gold ones. Planted in a mass on a slope it looks like a green waterfall.
- Flowing texture in shade
- Edging paths and steps
- Spilling over walls
What to plant with Japanese forest grass
Plants recorded as good partners for it, and what each pairing does:
- Hosta 'Halcyon': bold leaves against its fine ones; happy in the same moist soil.
- Astilbe: adds the flowers, late June to mid July; happy in the same moist soil.
- Japanese painted fern: happy in the same moist soil.
Choosing between it and a look-alike? Japanese forest grass vs Sedge 'Everillo'.
Questions about Japanese forest grass
Does Japanese forest grass need sun or shade?
Japanese forest grass grows in part sun (4 to 6 hours of sun, including some afternoon sun), part shade (2 to 4 hours of sun, mostly in the morning) and shade (less than 2 hours of direct sun, or bright dappled light). It is one of the few that also put up with deep shade.
It wants soil that stays evenly moist, rich in organic matter, and a good soak in dry spells.
What zones does Japanese forest grass grow in?
USDA zones 5 to 9. It is hardy to zone 5, which means it survives winter nights down to about −10 °F (−23 °C).
Gardening in Canada? Use the USDA zone for your town: Canada's own zone map uses different numbers.
How far apart should Japanese forest grass be planted?
18 in (45 cm) apart, from the middle of one plant to the middle of the next. That is a little closer than its full width of 24 in (60 cm), so a group knits into one patch.
It grows 18 in (45 cm) tall. Give it the full distance from anything taller, or it will lean out towards the light.
How many Japanese forest grass plants do I need?
At 18 in apart, set out in staggered rows:
- 5 to fill 10 square feet (about 1 m²)
- 7 for a single row 10 ft (3 m) long
- 17 to fill a 4 × 8 ft bed on its own
In a mixed border, plant it as runs of three or five along the front (or one even row, in a formal bed).
In the bed above, the planner used three in one group.
Is Japanese forest grass poisonous to dogs and cats?
No toxicity is recorded for dogs, cats, horses or people, according to NC State Extension.
"Not toxic" is not "edible": a pet that eats a lot of any plant can be sick.
Do deer eat Japanese forest grass?
Mostly not. NC State lists it as resistant to deer. No plant is proof against a hungry deer in a hard winter, but this one is low on the menu.
What does Japanese forest grass look like in winter?
Japanese forest grass turns the colour of straw and, left uncut, stands through the winter. Cut it down in late winter, before the new shoots come up.
More Hakonechloa
- Japanese forest grass 'All Gold' Hakonechloa macra 'All Gold'
- Japanese forest grass 'Aureola' Hakonechloa macra 'Aureola'
- Japanese forest grass 'Beni-kaze' Hakonechloa macra 'Beni-kaze'
In these guides
Every fact on record
- Type
- Grass
- Size
- 18 in (45 cm) tall, 24 in (60 cm) wide
- Plant
- 18 in (45 cm) apart
- Height class
- Short (12 to 18 in)
- Place in the bed
- Front
- Flowers
- None: grown for its foliage
- Leaves
- Fine texture, herbaceous; green
- Shape
- Arching, clumping
- Hardy in
- USDA zones 5 to 9
- Light
- Part sun, part shade, shade
- Soil
- Rich, evenly moist
- Water
- Moderate
- Feeding
- Light, in spring
- Family
- Poaceae
- Comes from
- Japan
- Stands up to
- Deer, deep shade, black walnut, pollution
Checked against NC State Extension. Flowering times are for zone 5: later in colder zones, earlier in warmer ones. Toxicity and spread information is a general gardening guide, not veterinary or medical advice, and invasive status varies by region. If a person or pet eats a plant, contact poison control or a vet. Check your local invasive species list before planting anything with a spread warning.