Bottlebrush grass
Elymus hystrix · Poaceae
Open, bristly seed heads like bottle brushes stand above the leaves in summer. A native grass of woodland, happy in dry shade.
- Size
- 3 ft tall, 16 in wide
- Zones
- 5 to 9
- Light
- Part sun to shade
- Flowers
- Late June to late August
- Pets
- No toxicity recorded
- Job in a bed
- Drift
A bed built around bottlebrush grass
The planner designed this bed around bottlebrush 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 bottlebrush grass stands where it does.
The plants
- 1 Bottlebrush grass × 5, green
- 2 Mossy saxifrage × 20, pink
- 3 Leadwort × 20, blue
- 4 Tall astilbe 'Superba' × 3, purple
- 5 Inkberry 'Gem Box' × 1, dark green leaves
- 6 Giant snowdrop × 12, white
- 7 Hardy cyclamen × 3, pink
Why this plant
- Part of the matrix. The low fabric of grasses and groundcovers that the taller plants come up through.
- The only spires. The others are open bowls, dense clusters, plumes and others. Shape reads at a distance, where colours blur.
- The only green. Green sits between stronger colours and calms them.
Why here
- Anchors a back corner. At 3 ft it is one of the taller plants here, and the tallest close the ends of the bed, where they stand in front of nothing.
- A step in the back row. Next to inkberry 'Gem Box' (2½ ft): no two neighbours there are the same height, so the back steps up and down like a skyline.
- 5 plants in one group. Massed, one kind reads as a single shape. Scattered, it would look spotty.
Why now
- In flower for 10 weeks. From late June to late August.
- Fills a gap. For five of those weeks nothing else 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 73% of the planted ground. It is planted in layers: about 8 in at the front, 18 in in the middle and 3 ft at the back. Pink, blue, purple, green and white make a cool, restful scheme.
The planner's own design check: 14 Excellent, 2 Good, 1 Satisfactory. 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 bottlebrush grass goes in a border
At 3 ft it belongs in the middle of a bed. In the planner's ten height classes it is medium tall (2½ to 3 ft). It is airy enough to see through, so it can also come forward and veil what is behind it.
Its job: drift. Planted in a small group of three or five, and repeated further along in the other number.
It brings the lightness of a grass into shade, where few grasses grow. Scatter it among woodland asters and ferns. It is short-lived, but self-seeds.
- Grasses for dry shade
- Native woodland edges
- Seed heads for arrangements
What to plant with bottlebrush grass
Plants recorded as good partners for it, and what each pairing does:
- White wood aster: a low mound at the foot of its spires.
- Blue-stemmed goldenrod: takes over when it finishes, flowering from early September.
- Christmas fern: its dark green leaves are a setting for the flowers, before and after; low enough (20 in) to stand in front of it.
Questions about bottlebrush grass
Does bottlebrush grass need sun or shade?
Bottlebrush 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 ordinary well-drained soil, of average fertility, and little watering once settled. Once settled in, it stands drought.
What zones does bottlebrush 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.
When does bottlebrush grass flower in my zone?
In zone 5 it flowers late June to late August. As a summer flower it moves about half a week for every zone: earlier where it is warmer.
| Zone 5 | Late June to late August |
|---|---|
| Zone 6 | Late June to late August |
| Zone 7 | Mid June to mid August |
| Zone 8 | Mid June to mid August |
| Zone 9 | Early June to early August |
Worked out from Hopkins' bioclimatic law: spring arrives about four days later for each degree of latitude north, and one zone is roughly two degrees. A warm spring or a cold one moves any garden two weeks either way.
How far apart should bottlebrush grass be planted?
16 in (40 cm) apart, from the middle of one plant to the middle of the next. That is about its full width, so each plant keeps its own outline.
It grows 3 ft (90 cm) tall. Give it the full distance from anything taller, or it will lean out towards the light.
How many bottlebrush grass plants do I need?
At 16 in apart, set out in staggered rows:
- 7 to fill 10 square feet (about 1 m²)
- 8 for a single row 10 ft (3 m) long
- 21 to fill a 4 × 8 ft bed on its own
In a mixed border, plant it as a group of three or five, with a second group further along in the other number.
In the bed above, the planner used five in one group.
Is bottlebrush grass poisonous to dogs and cats?
No toxicity is recorded for dogs, cats, horses or people, according to NC State Extension. Not poisonous, but the bristly seed heads can injure the mouths of grazing horses.
"Not toxic" is not "edible": a pet that eats a lot of any plant can be sick.
Do deer eat bottlebrush grass?
They may. NC State does not list it as resistant to deer or rabbits. Where they visit, protect it, or plant it among ones they avoid.
Will bottlebrush grass spread?
It seeds itself about; the risk of it taking over is moderate. Short-lived, but keeps going by self-seeding. Thin or move seedlings where they are not wanted.
What flowers after bottlebrush grass?
Bottlebrush grass is over by late August. These start as it finishes and carry the same spot on, so it never goes flat:
- Blue-stemmed goldenrod: from early September to mid October, 2½ ft tall (a recorded partner).
- White wood aster: from late August to early October, 24 in tall, to stand in front of it and cover its fading stems (a recorded partner).
- Japanese anemone: from mid August to early October, 3 ft tall.
What does bottlebrush grass look like in winter?
Bottlebrush grass turns the colour of straw and, left uncut, stands through the winter, with seed for the birds. Cut it down in late winter, before the new shoots come up.
Is bottlebrush grass good for bees and butterflies?
Bottlebrush grass is visited by songbirds.
It is a host plant: the caterpillars of northern pearly-eye feed on its leaves. A butterfly can only lay its eggs on its host plants, so these do more for it than any nectar flower.
It is native to the United States.
In these guides
- Plants for dry shade
- Plants for deep shade
- Plants that grow near black walnut
- Plants for slopes and banks
- Pet-safe plants for shade
- Native plants for shade
- Plants for butterflies
- Plants that feed garden birds
- Ornamental grasses under 3 feet
- Plants with spires: vertical accents
- Host plants for the northern pearly-eye
Every fact on record
- Type
- Grass
- Size
- 3 ft (90 cm) tall, 16 in (40 cm) wide
- Plant
- 16 in (40 cm) apart
- Height class
- Medium tall (2½ to 3 ft)
- Place in the bed
- Middle, or further forward: it is airy enough to see through
- Flowers
- Late June to late August; upright spires; green
- Leaves
- Medium texture, herbaceous; green
- Shape
- Upright, self-seeding
- Hardy in
- USDA zones 5 to 9
- Light
- Part sun, part shade, shade
- Soil
- Average, well-drained
- Water
- Low
- Feeding
- None needed
- Family
- Poaceae
- Comes from
- North, Central and Eastern U.S.A
- Attracts
- Songbirds
- Host plant for
- Northern pearly-eye
- Stands up to
- Drought, deep shade, black walnut, pollution, erosion
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.