Generally — Most Areas
ostrich fern (zones 3-7) suits most of Delaware (7a-8a) — zone 7 are in range, and the rest of the state is the exception.
Ostrich Fern in Delaware — the short answer
Ostrich Fern in Delaware: hardy in zones 3–7, shade, against a state median of ~241 frost-free days.
- Plant zones
- 3-7
- 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
- Delaware zones
- 7a-8a
- USDA PHZM 2023
- Frost window
- Mar 23 - Mar 23 – Nov 17 - Nov 19
- NOAA RCC ACIS 1991-2020, 28°F
- Shortest county season
- 238 days
- NOAA Regional Climate Centers ACIS, 1991-2020, county 28°F killing freeze
Plant data: Growable Ground Plant Database, compiled from FAO ECOCROP, USDA PLANTS and university Extension sources — per-field provenance varies and is published with the dataset.
Your yard isn't the whole zone.
Delaware spans zones 7a-8a, but your yard sits in exactly one — and slope, tree cover, and cold-air pockets nudge it further. Enter your address and we'll score ostrich fern against your parcel's actual hardiness, soil, and sun.
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Where Ostrich Fern Stands in Delaware
Ostrich Fern is rated for zones 3–7 — a cold floor USDA puts at -40 to -30°F. No Delaware county sits inside it, so in open ground this is a grown-under-cover plant here rather than a bed plant — which is a statement about Delaware winters, not about ostrich fern.
Above the zone 7 ceiling
3 counties
- Kent County · zone 7b
- New Castle County · zone 7b
- Sussex County · zone 7b
Too little winter chill rather than too much cold — a low-chill selection is what changes it.
County hardiness zones: USDA Plant Hardiness Zone Map (PHZM) 2023, per county. A zone is a 10°F band of average annual extreme minimum temperature, so the floor above is the band the plant's rating denotes, not a single measured kill point. Slope, shelter and cold-air drainage routinely move a site half a zone either way from its county figure — which is the part only your address resolves.
Zone Comparison
Ostrich Fern Needs
- USDA Zones: 3-7
- Sun: Shade
- Mature size: 5 ft tall
- Drought tolerance: Low
Delaware Has
- USDA Zones: 7a-8a
- Last Hard Freeze (28°F): Mar 23 - Mar 23
- First Hard Freeze (28°F): Nov 17 - Nov 19
- Annual Rainfall: 42-48 inches
- Common Soils: Sandy loam, Silt loam, Tidal marsh
Plant Zone Range (zones 3-7)
Preferred Soil pH
Plant data: Growable Ground Plant Database, compiled from FAO ECOCROP, USDA PLANTS, and university Extension sources — per-field provenance varies and is published with the dataset. State data: USDA ARS PHZM 2023, NOAA Climate Normals, NRCS SSURGO.
When to Plant Ostrich Fern in Delaware
The frost window
Across Delaware, the last spring hard freeze (28°F) clears between Mar 23 and Mar 23, and the first fall hard freeze lands between Nov 17 and Nov 19 (NOAA Regional Climate Centers ACIS, 1991-2020). Counting from the latest last freeze to the earliest first freeze, that's a 239-day window you can count on — up to 241 days on a mild site in a kind year. That marks the hard freeze, not the last light frost, so tender transplants usually wait another 2-3 weeks.
Winter standing
Delaware runs as cold as USDA zone 7, and no sourced winter-hardiness floor is on record for ostrich fern, so this page does not state whether it overwinters here — and gives no fall establishment date on the strength of a guess. Whether ostrich fern is a permanent planting or a replant-every-spring crop for you turns on your own zone within Delaware; check its hardiness range against that before treating it as long-lived ground.
Frost window: NOAA Climate Normals 1991-2020. Plant timing fields: Growable Ground Plant Database — frost-free days from FAO ECOCROP, days to harvest from university Extension production guides, and growing-degree-day and chill-hour minimums that are compilation estimates rather than published figures. Your site's own frost dates can run earlier or later than the state range — a parcel report pins them down.
Soil + Drainage Fit
Ostrich Fern likes near-neutral soil (pH 5-7). That's the common-ground band across Delaware's sandy loam and silt loam — a soil test confirms it for your site. It will grow across that whole span, but it does best between pH 5.5 and 6.5 — worth knowing before you decide whether a Delaware soil test result is a problem or just a number. Drainage requirement: poorly (saturated >50% of year). A soil-survey lookup (NRCS SSURGO) flags whether your specific site matches.
Plant pH requirements: FAO ECOCROP and USDA PLANTS, with the remaining rows from other published sources or Growable Ground compilation. Drainage: FAO ECOCROP, with the remaining rows from other published sources or Growable Ground compilation. Delaware soil profile from USDA NRCS SSURGO. Site-specific verification: a 30-minute soil test from your local Extension lab.
What Else to Consider for Ostrich Fern in Delaware
Zone compatibility tells you about winter cold survival — but Delaware growers also need to think about:
Sandy soils in southern DE drain too quickly
Salt spray damage near the coast
Rising water tables in low-lying areas
What to actually do about these — and the constraints that apply to every Delaware grower, not just ostrich fern — is covered on the Delaware growing guide.
Where in Delaware Ostrich Fern Is Zone-Hardy
Ostrich Fern is rated for USDA zones 3–7. Every Delaware county sits above it. Even Kent County, the state’s coldest at zone 7b, is milder than the plant’s zone 7 ceiling — the constraint here is winter chill it will not get, not cold it cannot take.
County hardiness zones: USDA Plant Hardiness Zone Map (PHZM) 2023, per county. Ostrich Fern’s zone 3–7 band: USDA PLANTS / Growable Ground plant database. A parcel report resolves your address’s own zone and frost dates rather than its county’s.
Pollinator + Wildlife Value
Deer pressure is meaningful across much of Delaware; ostrich fern is listed as deer-resistant (USDA PLANTS Database), which makes it a safer pick for unfenced sites. Our deer & wildlife guide carries the full deer-resistant list and how to protect the rest.
Delaware Cooperative Extension
For Delaware-specific cultivar recommendations, planting calendars, and pest pressure for ostrich fern, the canonical source is University of Delaware Cooperative Extension. Their fact sheets carry the local trial data we can't generalize across 50 states.
Is Ostrich Fern native to Delaware?
Ostrich Fern is native to parts of the Lower 48, but the USDA PLANTS Database (accessed 2026-07-01) does not document a native range in Delaware. It can still earn a place in a Delaware garden — the zone comparison above tells you whether it will thrive.
Looking for plants that belong here? The Delaware growing guide lists USDA-documented natives for the state.
Native-range data: USDA PLANTS Database state-distribution records, accessed 2026-07-01.
Common Questions About Growing Ostrich Fern in Delaware
When can I plant Ostrich Fern in Delaware?
Delaware's last spring hard freeze (28°F) clears between Mar 23 and Mar 23, and the first fall hard freeze lands between Nov 17 and Nov 19 (NOAA Regional Climate Centers ACIS, 1991-2020). No sourced winter-hardiness floor is on record for Ostrich Fern, so this page does not state whether it overwinters in Delaware and publishes no fall establishment date for it — check its hardiness range against your own zone before treating it as a permanent planting.
What hardiness zone is Ostrich Fern grown in across Delaware?
Delaware spans USDA hardiness zones 7a-8a (USDA ARS PHZM 2023). Ostrich Fern carries a range of zones 3-7, so the overlap zones are where outdoor growing is most reliable.
How many frost-free days does a typical Delaware site have?
A typical Delaware site sees ~241 frost-free days per year (derived from NOAA Regional Climate Centers ACIS, 1991-2020). Ostrich Fern should be matched against that window, so check whether your local microclimate runs above or below the state average before settling on a planting date.
Is Ostrich Fern native to Delaware?
Ostrich Fern is native to parts of the Lower 48, but the USDA PLANTS Database (accessed 2026-07-01) does not document a native range in Delaware. It can still earn a place in a Delaware garden — the zone comparison above tells you whether it will thrive.
How should I amend the soil for Ostrich Fern in Delaware?
Ostrich Fern prefers pH 5-7 and poorly (saturated >50% of year) drainage (Growable Ground Plant Database). That sits in the common-ground band across Delaware soils — a 30-minute soil test from a local Extension lab confirms it for your specific site.
Will Ostrich Fern actually grow on my specific land in Delaware?
State-level zone + climate data is a sketch. A Growable Ground parcel report scores ostrich fern against your address's exact soil pH, drainage, sun, and frost-date data drawn from USDA SSURGO, NOAA, and PRISM — not state averages.
Check your specific parcel in Delaware
State-level data is a sketch. Your Growable Ground report scores ostrich fern against your parcel's exact soil, sun, drainage, and frost data — not zone averages.
Three things about your lot that Delaware ostrich fern averages can't show:
We read public map data around Delaware — soil, climate, flood, and parcel records. How we handle your address.
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Explore More
Growing guides for ostrich fern
Explore Delaware county by county
Delaware carries 3 counties with their own USDA zone — a sample of the growing pages for ostrich fern there:
Where else ostrich fern grows
Ostrich Fern's zone band crosses state lines — these are the states closest to Delaware in winter climate where it also has a page, plus the far ends of its range. Each one re-answers the question with that state's own record.
More to grow in Delaware
Delaware has a growing page for 1,013 plants — a rotating sample of the rest of the shelf.
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