Onoclea sensibilis (Sensitive Fern)
| Also known as: | |
|---|---|
| Genus: | Onoclea |
| Family: | Dryopteridaceae (Wood Fern) |
| Life cycle: | perennial |
| Origin: | native |
| Habitat: | part shade, shade, sun; moist woods, thickets, wet meadows, swamps, pond edges |
| Fruiting season: | summer |
| Plant height: | 12 to 30 inches |
| Wetland Indicator Status: | GP: FACW MW: FACW NCNE: FACW |
| MN county distribution (click map to enlarge): |  |
| National distribution (click map to enlarge): |  |
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Detailed Information
Fiddlehead:
![[photo of fiddleheads]](/udata/r9ndp23q/ferns/sensitive-fern-_0508_113927.jpg)
Plants emerge in early spring, typically dark red stems with short white hairs on the back of the unfurling leaves and a few brown scales scattered along the stem. The hairs persist along the leaf veins and midribs.
Leaves and stems: 
![[photo of sterile frond]](/udata/r9ndp23q/ferns/sensitive-fern-100_4172.jpg)
Leaves are once compound, 12 to 30 inches tall, erect to arching, triangular to egg-shaped in outline, yellowish to medium green. Leaflets are widely spaced, generally lance-elliptic, 5 to 11 on each side of the stem, with a network of veins on the underside. The upper leaflets often have smooth edges while lower leaflets tend to be shallowly to deeply lobed and may be wavy. The stem is dark brown to black and flattened at the base, and winged along much of the upper part of the leaf. One to a few leaves are irregularly spaced along a creeping rhizome.
Spores:
![[photo of fertile frond]](/udata/r9ndp23q/ferns/sensitive-fern_8338.jpg)
At least 1 spike, 8 to 20 inches tall, develops in early summer. 5 to 11 pairs of branches contain the spores in bead-like structures tightly packed along a branch. These fertile fronds turn brownish black at maturity and persist through winter, releasing the spores the following year.
Notes:
Sensitive Fern likely gets its common name from its intolerance for cold, the sterile fronds dying at the first frost. It is easy to identify, as nothing else in Minnesota looks quite like it, though the fertile fronds of Ostrich Fern (Matteuccia struthiopteris var. pensylvanica) are similar and also persist through winter. Ostrich fern has 25 or more pairs of branches on its fertile fronds and is typically taller than Sensitive Fern. Sensitive Fern tolerates both shade and sun and does well enough in a home garden with adequate moisture. The bright green leaves are eye-catching. It can form colonies from its long rhizomes, creating a thick mat of roots.
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More photos
Sensitive Fern plants
underside of leaflet
garden grown Sensitive FernPhotos by K. Chayka taken in Ramsey County. Photos courtesy Peter M. Dziuk taken in a private garden in Anoka County.
Comments
Have you seen this plant in Minnesota, or have any other comments about it?
on: 2012-07-28 22:19:47
Have been clearing our oak forest of buckthorn. Found two patches of this in wet, shady areas. One area is near a pond in a grassy area. The other patch is in the woods, in an area where jack in the pulpits seem to be emerging, too. Nice to see habitat recovering when the buckthorn is removed.
on: 2018-06-09 21:55:06
Daughter clearing brush at back of her lot, found sensitive ferns and jack-in-the-pulpit.
on: 2018-06-22 07:57:46
We have a couple of thick colonies of sensitive ferns - one in an open grassy area and one in the shade, and individual plants scattered about the property. They seem to crowd out everything else once they get going so I'm afraid they'll take over a grassy field.
on: 2018-07-17 12:48:26
It showed up in my lawn a week ago. Fortunately, I didn't cut it off and will move it now that I know what it is.
on: 2020-03-23 03:54:24
An attractive smaller fern that likes moist soils in shady areas, they form a slowly spreading clump and in the woods can form large colonies around low areas. Long-lived and has done well in our wildflower garden mixed with Trillium, Violets, and Wild Ginger. The sporangia spikes make exceptionally long persisting dried material for indoor decorations. Like many ferns, not eaten by deer
on: 2020-07-11 19:28:35
This fern is growing in an oak forest next to my farm, it is also spreading into a large open area in our property that we have let reforest (it was once an winter rye and hay field). The area is hilly and I have found the sensitive fern growing in the lower lying areas along with various grasses, prairie willows and sedges.
on: 2021-05-17 15:47:06
Good patch of these just unfurled, 5-17- 2021.
on: 2021-06-23 10:13:05
Have a thick patch along my driveway. The light green caught my eye so looked them up. Growing in mostly shade in a low wet area where purple iris are as well. Would like to transplant some closer to the house near the pond.
on: 2021-08-31 12:23:21
These lil' guys, along with another species of fern I can't ID started taking over my very urban front yard last year. I live at a low-draining area in Frogtown and I guess they like it here. They do make it a challenge to mow. Good thing we've been in a drought all summer; although they seem to be unaffected by it. Tried transplanting a few last fall and not one survived. Any ideas?
on: 2024-07-17 16:12:22
Last few drought years has caused massive invasion of none specie plants around home and woodlands. Been pulling invasive species. Thrilled to identify and learn that the new fern clumps making the terrace landscape its new home amongst my other ferns and plants under our deck in the woodchips and near bird baths is native.