Winter Ferns 2025-2026

Sensitive & Ostrich Ferns

This year we have a good blanket of snow, so it is harder to find winter ferns that are not under the snow. For most winter ferns, the fertile fronds disintegrate before winter and only the sterile fronds remain. But the Sensitive Fern (Onoclea sensibilis) and Ostrich Fern (Matteuccia struthiopteris) have feritle fronds which persist through the winter. The Sensitive Ferns are on the left and the Ostrich Ferns on the right. They are both in the Onocleaceae or Sensitive Fern Family.

They both have sturdy fertile fronds with rolled edges of the pinnae (leaflets) covering the sori (fruitdots) until they are mature and have the right conditions to be released. Most fern books state that the fertile fronds don't release their sori until the Spring, but if you look carefully you may find some that have already opened and released them. I used two examples of each species in this photo to show the usual fertile fronds with the sori still protected (on the outer edges of the group) and also two that have already opened and released the sori (the two inner fronds). If you look closely at them you will see the tight beadlike structures of the first, and the more skeletal remains of the opened protective structures with the sori released on the inner ones. The Sensitive Fern frond with the released sori is not entirely spent so will look a little more open with time.

The Sensitive Fern fronds are smaller in height and width than the Ostrich Fern, and the Ostrich Fern fronds have pinnae which get smaller and smaller down the stem. They are pretty easy to tell apart, even from a distance.

Posted: to PV Fern News on Sat, Jan 24, 2026
Updated: Sat, Jan 24, 2026