River Mist (Chasmanthium latifolium 'River Mist') - white flowers, illustrated plant cardIllustration

River Mist

Chasmanthium latifolium 'River Mist'

River Mist blooms from July through September.

Bloom calendar
Bloom time
Jul–Sep
not yet checked
Hardiness
Zones 3–8
checked
Sun
Part shade
checked
Water
Moderate water
not yet checked
Mature size
3 ft × 2 ft
checked
Type
Grass
house classification

Months here are Northern Hemisphere months; in the Southern Hemisphere, shift them by six months.

Growing River Mist

Plant it in part shade. It prefers moderate water. It is hardy in USDA zones 3–8. Expect it to reach about 3 ft tall and 2 ft wide at maturity, in roughly 2 years (not yet checked).

No toxicity note is on file for River Mist. That is not a clearance: check its safety for people and pets before planting.

Verification
What was checked

Mature height and spread, hardiness zones, sun and the trait tags were checked against named botanical sources for this plant. The bloom months and water need on this page were not, and each fact above says which. The planting, spacing and size sections are derived from these checked facts by a fixed rule, not checked separately, and the plant type is the library's own classification.

See the 5 sources it was checked against

When to plant River Mist

Plant River Mist in early spring as soon as the soil is workable, or in early fall at least six weeks before your first frost, so roots establish in cool weather. In zone 5, the middle of its hardy zones 3 to 8, spring means April to June and fall means August or September. Once settled, it blooms from July to September.

Month-by-month timing for your zone is on the planting calendar; if you garden near zone 5, the middle of this plant's hardy range, start with zone 5 in April. Derived from the plant's category, zones and bloom months plus typical zone frost dates, not checked separately.

How big does River Mist get?

Illustration of River Mist drawn to scale beside an adult3 fttall5 ft 7 inan adult2 ftwide
About 3 ft tall and 2 ft wide at maturity: waist-high beside an adult.

See River Mist in a garden plan: the planner shows it in 3D beside everything else you add, growing toward this size over the years.

How far apart to plant River Mist

Derived from the mature spread above by a fixed rule, not checked separately: spacing is the spread, center to center.

Space River Mist about 2 ft apart, center to center, so each plant has room to reach its full width.

Plant them
2 ft apart
Per 10 sq ft
about 3
4 by 8 ft bed
about 8

Add River Mist to a garden plan and the planner draws it at its full width, so you see the spacing before you buy.

Where these facts come from

River Mist's height, spread, hardiness zones, sun and trait tags were checked against 5 published sources on July 29, 2026. Each one is linked below with every fact it carried, which can include a fact this page still marks as not yet checked, because a source carrying a value is not the same as the value being held to the standard. Facts not in that list, and the planting, spacing and size sections, are not covered by these sources.

How the checking works, and what each standard covers, is on the verified plants page.

The Northern Sea Oats group

One of 2 in the Northern Sea Oats group. Same plant, same care.

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Design a garden with this

Drop this plant onto a 3D plan, see how it fills in, and watch your whole garden bloom across the year.

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