sword fern (Polystichum munitum), photographi

How to Grow Sword Fern

Polystichum munitum · Zones 4-10

Sword Fern is a perennial grown for its brown blooms, which open in summer and return year after year. It's hardy across USDA zones 4 through 10 and shrugs off deer.

Sword Fern — the short answer

Sword Fern: grown in zones 4–10, part sun, pH 5.8–7.5.

USDA zones
4–10
Manual horticultural correction (source not retained); NC State Extension and Missouri Botanical Garden, with the remaining rows from other published sources or Growable Ground compilation
Soil pH
5.8–7.5
USDA PLANTS
Sun
Part Sun
Growable Ground Plant Database

Plant data: Growable Ground Plant Database, compiled from FAO ECOCROP, USDA PLANTS and university Extension sources — each tile names its own row's source, because per-field provenance varies.

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What Sword Fern is

Sword Fern grows as a perennial and reaches around four feet at maturity. It blooms brown in summer. It's also deer-resistant.

How to grow Sword Fern

Sword Fern grows in USDA zones 4 through 10. Sword Fern does best in part sun — at least 4 hours of direct sun a day — and soil from pH 5.8 to 7.5, on consistently moist ground.

USDA Zones

4-10

USDA PHZM 2023

Soil pH

5.8 - 7.5

USDA PLANTS

Sun

Part Sun

Growable Ground plant catalog

Drainage

poorly (saturated >50% of year)

Growable Ground plant catalog

Cold Hardiness

-33°F

The coldest temperature this plant is documented to survive.

USDA PLANTS

Mature Height

4 ft

Growable Ground plant catalog

Frost-Free Days

0+

The frost-free stretch it needs start to finish — short-season areas may need an indoor head start.

Growable Ground plant catalog

  1. Start the season right

    Plant sword fern in part sun with at least 4 hours of direct sun.

  2. Match the soil

    Sword Fern prefers pH 5.8 to 7.5 (USDA PLANTS). A quick soil test from your local Extension lab tells you whether to add lime or sulfur to land in band.

  3. Water steadily

    Keep the root zone evenly moist through establishment. Match watering to the plant's drainage preference and your local rainfall.

  4. Harvest at its peak

    Cut sword fern blooms in the cool of the morning, just as they open, for the longest display.

Where Sword Fern thrives

Sword Fern is hardy across USDA zones 4 through 10. Zone is only the starting point, though: the soil pH, drainage, and frost dates on your specific land decide how well it actually does.

A USDA zone is a 10°F band of average annual extreme winter minimum, so zones 410 spans average winter lows from -30°F to 40°F (USDA PHZM 2023). Across the 50 states and DC, that band covers 38 outright and splits 13 more down the middle — and which side of that line your land sits on changes the answer.

Zones 4–10 highlighted on the USDA national hardiness zone map

Zones 4–10·Where Sword Fern growsOpen map →

Where Sword Fern stands, state by state

Sword Fern is rated for zones 410 — a cold floor USDA puts at -30 to -20°F. Across the 50 states and DC, 38 sit fully inside that band, the line runs through 13 more, and 0 sit outside it — and inside every split state, the same line runs on at county grain.

Fully inside zones 4–10

38 states

3 of 38 shown

The line runs through

13 states

3 of 13 shown

Sword Fern’s band covers part of each of these states — which side of the line your county sits on changes the answer, and each state page draws it.

State zone extents: USDA Plant Hardiness Zone Map (PHZM) 2023. A zone is a 10°F band of average annual extreme minimum temperature, so a state that splits the band contains the boundary — its own page draws the county line, and a parcel report resolves which side your land sits on.

What grows around Sword Fern

In rotation planning, sword fern counts as a Other — beds recover best when other crops don’t follow each other in the same spot year over year. (Growable Ground derivation — crop-rotation group from botanical family)

Good to know

Good news for pet owners — sword fern isn't known to be toxic to dogs or cats. (Source: ASPCA.)

Sword Fern isn't classified as a notable pollinator plant in our data — pair it with high-value bloomers nearby to feed bees.

Your land is one point inside Sword Fern's range

This page resolves to the species. Your state page draws the county line, and a report reads the parcel — the soil pH, drainage, sun, and frost dates on your exact ground, which no species average can see.

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See if Sword Fern will thrive on your land

Zone averages are a start. Your exact soil pH, drainage, sun exposure, and frost dates shape whether sword fern actually takes — we score it against the real conditions at your address.

Three things about your exact spot that zone averages miss:

Your soil pHYour frost-free daysYour sun & shade

We read public map data for this spot — soil, climate, flood, and parcel records. How we handle your address.

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How we know this about Sword Fern

The figures above are cited per row, not per site: the pH band names this plant’s own source column, the three temperature figures each carry their own, and days-to-maturity cites the publication that actually lists it. All of it comes from the Growable Ground Plant Database — a compilation over FAO ECOCROP, USDA PLANTS, and university Extension sources, published openly with per-field provenance.

Grounded inUSDA PLANTS DatabaseUSDA PHZMASPCA

Frequently asked questions

Can I grow Sword Fern in my zone?

Sword Fern grows in USDA hardiness zones 4 through 10 (USDA PHZM 2023). Zone is one factor — soil pH, drainage, and frost dates on your specific parcel also shape whether it takes.

When should you plant Sword Fern?

Time sword fern to your own season rather than the calendar. Your local frost dates set the exact window — a Growable Ground report reads them for your address.

How much sun does Sword Fern need?

Sword Fern does well in partial sun — around 4 hours of direct sun, and it takes some afternoon shade in stride. That flexibility makes it a good match for a bed the house or a nearby tree shades for part of the day. A Growable Ground report maps how the sun actually falls on your land, hour by hour, so you can set it where the light lines up.

What soil does Sword Fern need?

Sword Fern prefers soil pH 5.8 to 7.5, on consistently moist ground (USDA PLANTS). Your report scores your parcel's actual soil against that using USDA SSURGO data.

Does Sword Fern attract pollinators?

Sword Fern isn't classified as a notable pollinator plant in our data. Pairing it with high-value bloomers nearby keeps bees and butterflies fed.

Is Sword Fern safe for pets?

Sword Fern is not known to be toxic to dogs or cats based on available data. Always supervise pets around new plantings. (Source: ASPCA.)