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Cinnamon Fern
Osmundastrum cinnamomeum
Cinnamon Fern is grown for its foliage rather than flowers, giving the garden structure and color all season long.
Months here are Northern Hemisphere months; in the Southern Hemisphere, shift them by six months.
Growing Cinnamon Fern
Plant it in part shade. It prefers high water. It is hardy in USDA zones 3–9. Expect it to reach about 3.5 ft tall and 2.5 ft wide at maturity, in roughly 3 years (not yet checked).
No toxicity note is on file for Cinnamon Fern. That is not a clearance: check its safety for people and pets before planting.
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.
When to plant Cinnamon Fern
Plant Cinnamon Fern 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 6, the middle of its hardy zones 3 to 9, spring means March to May and fall means August or September.
Month-by-month timing for your zone is on the planting calendar; if you garden near zone 6, the middle of this plant's hardy range, start with zone 6 in March. Derived from the plant's category, zones and bloom months plus typical zone frost dates, not checked separately.
How big does Cinnamon Fern get?
3.5 fttall5 ft 7 inan adult2.5 ftwideSee Cinnamon Fern 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 Cinnamon Fern
Derived from the mature spread above by a fixed rule, not checked separately: spacing is the spread, center to center.
Space Cinnamon Fern about 2.5 ft apart, center to center, so each plant has room to reach its full width.
Add Cinnamon Fern 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
Cinnamon Fern's height, spread, hardiness zones, sun and trait tags were checked against 4 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.
- NC State ExtensionPlant Toolboxheight, spread, hardiness zones, sun and trait tags
- Missouri Botanical Gardenheight, spread, hardiness zones and sun
- Lady Bird Johnson Wildflower Centerheight, hardiness zones and sun
- tnyards.utk.eduUniversity of Tennessee Extension (Tennessee Smart Yards)height, spread and sun
How the checking works, and what each standard covers, is on the verified plants page.
Good to know about Cinnamon Fern
Curated from university extensions, botanic gardens and other primary sources, with the source named on every note. A note reports what its source says; where that differs from a fact above, the fact above is this entry's stored value, and its mark says whether it has been checked.
Worth knowing
Its name comes from stiff, erect fertile fronds that turn cinnamon-brown in the center each spring, standing like cinnamon sticks before withering by early summer. per NC State
Zone range varies by source
Sources split on the cold floor: zone 3, a warmer 4, or a colder 2. The native range reaches Newfoundland and Minnesota, so the colder readings are well justified. per Missouri Botanical Garden and NC State
Wants wet feet
A wetland fern that needs constantly moist to wet ground; it scorches if the soil dries out. Ideal for rain gardens and damp, shaded low spots. per Clemson
Sun depends on moisture
How much sun it takes is really a moisture question: it accepts more sun only where soil stays reliably wet, and scorches in dry ground or hot sun. per NC State
Deer and pest resistant
Highly resistant to deer, tolerates rabbits and even black walnut, and has essentially no serious insect or disease problems, so it needs almost no spraying. per NC State and Missouri Botanical Garden
Slow clumper, not a runner
It builds a stout crown on compact rhizomes and expands only slowly, forming colonies gently in wet ground rather than running aggressively like ostrich fern. per Native Plant Trust
What pairs well with Cinnamon Fern
Good companions share its growing conditions and add something it lacks: an earlier or later bloom, a lower carpet in front, or structure through winter.
Christmas Fern
Takes part shade to full shade and moderate to high water; evergreen, so the bed keeps its shape through winter; lower at 1.5 ft, for the front of the border; both are North American natives.
Eastern Hemlock
Shares part shade and moderate to high water; evergreen, so the bed keeps its shape through winter; both are North American natives.
Bergenia
Takes part sun to part shade and moderate to high water; evergreen, so the bed keeps its shape through winter; lower at 1.5 ft, for the front of the border.
Wild Ginger
Takes part shade to full shade and moderate to high water; low at 6 in, to carpet the ground beneath; both are North American natives.
Autumn Fern
Shares part shade and moderate to high water; evergreen, so the bed keeps its shape through winter; lower at 1.5 ft, for the front of the border.
Holly Fern
Takes part shade to full shade and moderate to high water; evergreen, so the bed keeps its shape through winter; lower at 1.5 ft, for the front of the border.
Japanese Forest Grass
Shares part shade and moderate to high water; its seed heads stand through winter, for structure and the birds; lower at 1.5 ft, for the front of the border.
Hellebore
Shares part shade and moderate to high water; evergreen, so the bed keeps its shape through winter; lower at 1.5 ft, for the front of the border.
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