Japanese forest grass Hakonechloa macra
Japanese forest grass (Hakonechloa macra) is a deciduous perennial grass in the Poaceae family, native to Wet mountain cliffs of central Honshu, Japan. It grows 30–50 cm (12–20 in) tall and 40–60 cm (16–24 in) wide, wants part sun to part shade and moderate water, and is hardy to about -29 °C (-20 °F). Space plants about 45 cm (18 in) apart.
Plan Japanese forest grass in your garden →
Free. Draw your beds, then watch it grow through the year in 2D and 3D.
Japanese forest grass at a glance
| Type | Perennial grass, deciduous |
|---|---|
| Family | Poaceae |
| Mature height | 30–50 cm (12–20 in) |
| Mature spread | 40–60 cm (16–24 in) |
| Spacing | 45 cm (18 in) centre to centre |
| Sun | Part sun to part shade, at least 3 h of direct sun a day |
| Water | Moderate; drought tolerance low, waterlogging tolerance low |
| Soil pH | 5.5–7 |
| Cold hardiness | About -29 °C (-20 °F) once established (roughly USDA zone 4) |
| Heat stress | Likely above about 30 °C (86 °F) |
| Flowering | from about August for 4–9 weeks (northern hemisphere; later in cold climates, earlier in warm ones) |
| Wind tolerance | Low |
| Pollinator value | None |
| Edible | Not grown as food |
| Native to | Wet mountain cliffs of central Honshu, Japan |
| Common in gardens of | 🇯🇵 Japan, 🇬🇧 United Kingdom, 🇺🇸 United States |
Is Japanese forest grass toxic?
- People: not known to be toxic
- Cats: not known to be toxic
- Dogs: not known to be toxic
No toxicity reported in ASPCA or standard poison references.
If a child or pet may have eaten part of a plant, call a poison centre or vet straight away.
Companion planting: what to grow with Japanese forest grass
No well-documented helpful pairing. Group it with plants that like part sun to part shade and moderate water.
See Japanese forest grass in a botanical garden
It grows in these sample gardens, which you can walk through in 3D:
- Denver Botanic Gardens (10 plants)
- Riverside botanical garden (10 plants)
Questions about Japanese forest grass
- How far apart should I plant Japanese forest grass?
- About 45 cm (18 in) apart, centre to centre. A mature plant spreads 40–60 cm (16–24 in).
- Does Japanese forest grass need full sun?
- Part sun to part shade: at least 3 hours of direct sun a day.
- How much water does Japanese forest grass need?
- Moderate water. Drought tolerance is low and waterlogging tolerance low.
- How cold-hardy is Japanese forest grass?
- It tolerates about -29 °C (-20 °F) once established, roughly USDA zone 4.
- When does Japanese forest grass flower?
- From about August for 4–9 weeks (northern hemisphere; later in cold climates, earlier in warm ones).
- Is Japanese forest grass poisonous to cats and dogs?
- For cats it is not known to be toxic; for dogs not known to be toxic; for people not known to be toxic. No toxicity reported in ASPCA or standard poison references.
- What grows well with Japanese forest grass?
- There is no well-documented companion pairing for Japanese forest grass. Group it with plants that like the same sun (part sun to part shade) and water (moderate).
Sources and evidence
Evidence grade B (B: extension service or peer-reviewed).
- RHS Plant Finder, Royal Horticultural Society
- Missouri Botanical Garden Plant Finder, Missouri Botanical Garden
- Plants of the World Online (taxonomy, native range), Royal Botanic Gardens, Kew
Notes and assumptions
- Slow to establish; flowers are inconspicuous and late. Golden cultivars such as Aureola need partial shade to avoid scorch.
Reference values for planning, not horticultural, veterinary or medical advice. Varieties, soils and local climates differ: check with a local nursery or extension service.
Related plants
- Fountain grass Pennisetum alopecuroides
- Sweet corn Zea mays var. saccharata
- Lemongrass Cymbopogon citratus
- Clumping bamboo Fargesia murielae
- Maiden grass (miscanthus) Miscanthus sinensis
- Golden bamboo Phyllostachys aurea
- Switchgrass Panicum virgatum
- Little bluestem Schizachyrium scoparium