Carex pensylvanica, Pennsylvania Sedge

~These are divisions of an established patch in an area that is slated for disturbance in the near future~

Carex pensylvanica

Pennsylvania Sedge

  • Average to moderately dry soils
  • Part shade to full shade
  • 6" to 12” tall, 8” to 16” spread
  • Spring blooming, summer seed heads
  • Native to Ontario, Open Woodland and Forest ecosystems

There’s a Sedge for that.

Of the various genus of plants within Canada, Carex is the one that includes the most species by far. There are sedges that thrive is wet locations, dry areas, full sun and deep shade. They grow in meadows, forests and on beaches. They are short, tall, clump forming, fast spreading and everything in between.

My appreciation for this genus began to grow when my husband and I purchased a deed for 9 acres west of Perth and I started working with the sand/silt slightly acidic post glacial soils that can often be found on high and dry areas of shield rock. In any of the areas that receive some sun in the spring and dappled light in the summer, sedges thrive.

The carpet of Carex pensylvanica below the stands of Red Oak are particularly eye catching. The affinity of these two species is the source of this Sedge’s other common name, Oak sedge.

Like many, if not most, sedges, these are semi-evergreen, keeping the soil well protected through the winter and holding on to any available leaf litter. A trait that likely contributes to their ability to thrive in very lean soils.

Their blooms are pale gold tufts that appear very early in the spring, just after the snow melts and their new leaves are beginning to emerge. After blooming, their foliage grows to around 8” tall, often arching over a bit to a height of 4” to 6” as the summer heat arrives. They remain green and full through the summer except for years of extreme drought, when they brown a bit but bounce back once the weather cools.

Despite their grass-like appearance, most sedges are not tolerant of regular foot traffic. Where they do fit well into urban and other human centered landscapes is as species that tie plant communities together, filling in the spaces around and below other species and along the edges with foliage and the soil with dense roots, all of which is important to sustaining long-term ecosystem health.

As the most common ground covering species at my Perth place, these often pop up in the vegetable garden beds. Rather than weeding them I tried relocating several to the Ottawa gardens a couple of years ago. They didn’t seem terribly happy with their new home during their first year but, to my surprise, filled in beautifully this spring. If you look closely, you can spot them as supporting cast around the Violets and Bloodroots of earlier posts in this series. Given how well these fill the spaces below and between other species, they are one of the plants that I would recommend as a #nativegroundcover

The population of Sedges in the Perth forest includes far more than Oak Sedge but I have yet to learn all of their names and preferences. A book that I’ll be adding to my collection sometime in the not-too-distant future to help build by knowledge of the genus is Sedges of the Northern Forest: A Photographic Guide, by Jerry Jenkins, a book packed with technical information on differentiating 236 different species of sedge that can be found in the North East.

In the mean time, I’ve purchased seeds of a few more Carex species native to Ontario (Carex vulpinoidea - Brown Fox Sedge, Carex sprengelii - Long-beaked Sedge and Carex eburnea - Ivory Sedge) from Prairie Moon nursery and will be getting to know how these do in urban settings over the next couple of growing seasons.

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