A few years ago, I had the opportunity to create a new garden bed toward the front of the property. It was a little too far away from the spigot so watering was going to be an issue and quite possibly deer. I wanted native shrubs but my saplings were going to take time to mature, thus leaving bare space for a few years. Having a new bed as a blank canvas is great but you have a lot of “blank” until the saplings mature.
I thought I would cover the soil with groundcovers and had heard great things about the genus Carex. I visited the local nursery and selected several Carex “Evergold” plants. In fact, this well-known local garden center only had the brightly variegated cultivars of Carex. But I liked the fact that its graceful arching leaves added color to the garden and stayed evergreen in the winter. True to form, the plants performed well despite the lack of watering. Deer have not bothered them (although they did enjoy the oakleaf hydrangea). In fact nothing has bothered the plants – they are work horses in my Virginia garden.
So when I saw the new Mt. Cuba Center Research Report on Carex for the mid-Atlantic region at a nursery trade show this past week, I picked up a copy. The 24-page publication is great. There are many detailed photos illustrating the botanical structure of the plant, photos of the top performers, and charts. The report can be downloaded from Mt. Cuba Center.
In 2017, Mt. Cuba Center’s Trial Garden staff planted 70 different types of Carex, 65 species and five cultivars (no, not my ‘Evergold’). Carex are grass-like perennials that are found in diverse habitats from wetlands to coastal sand dunes. A member of the Cyperaceae plant family, Carex is a sedge. Its stems are triangular with three edges and a solid interior. Usually their flowers are grass-like and insignificant but there are a few with larger, more pronounced flowers. The plants can be clumping or spreading. They are evergreen, semi evergreen, or deciduous in the winter. Most gardeners use them as groundcovers or as a “spiller” in a large container. They also can be used to stabilize soil, prevent erosion, and serve as a turf alternative.
For four years, the Trial Garden staff evaluated the plants for their horticultural qualities, vigor, and adaptability. They were planted in the fall of 2017 and given supplemental water for the first year to get established. From then on, they did not get supplemental water, they were not fertilized, and they only received a late winter cutback. Each plant was assessed in both full sun and shade and in average soil. The plants were rated on a scale of 1 to 5 with 1 being very poor and 5 being excellent. Top performers are in the 4.2 range or higher, but the report does caution that those plants with lower scores are not necessarily inferior. They may be useful or good performers in other conditions (more wet or more dry soils).
Top performers are listed below. The report provides a full paragraph and one to two photos for each.
- C. woodii (Wood’s sedge): 4.7 shade rating, 4.4 sun rating
- C. cherokeensis (Cherokee sedge): 4.7 shade rating, 4.3 sun rating
- C. bromoides (common brome sedge): 4.6 shade rating, 4.3 sun rating
- C. haydenii (Hayden’s sedge) 4.5 shade rating, 4.5 sun rating
- C. stricta (upright sedge) 4.2 shade rating, 4.5 sun rating
- C. emoryi (Emory’s sedge) 4.1 shade rating, 4.4 sun rating
- C. sprengelii (long-beaked sedge) 4.4 shade rating, 4.0 sun rating
- C. pensylvanica (Pennsylvania sedge) 4.3 shade rating, and 4.2 sun rating
- C. pensylvanica ‘Straw Hat’ (Straw Hat Pennsylvania sedge) 4.4 shade rating, 4.1 sun rating
- C. muskingumensis ‘Little Midge’ (Little Midge Muskingum sedge) 4.3 shade rating, 5.2 sun rating
- C. albicans (white-tinge sedge) 4.3 shade rating, 4.1 sun rating
- C. jamesii (James’s sedge) 4.3 shade rating, 3.9 sun rating
- C. muskingumensis ‘Oehme’ (Oehme Muskingum sedge) 4.1 shade rating, 4.4 sun rating
- C. crinita (fringed sedge) 4.0 shade rating, 4.2 sun rating
- C. leavenworthii (Leavenworth’s sedge) 4.2 shade rating, 3.7 sun rating
- C. plantaginea (plantain-leaf edge) 4.2 shade rating and failed to thrive in full sun and did not complete trial for sun rating
Because Carex plants are wind pollinated, there is no benefit to pollinators, but the plants are important as host plants and for habitat. Small mammals and birds eat the seeds and caterpillars of butterflies and moths consume the leaves. Toads, frogs, and turtles like to take up residence in the plants.
The report also assessed Carex as a lawn alternative. In 2022, they did a year long mowing trial to identify which ones would be tolerant of regular mowing, grown both in sun and shade. Most were tolerant but those with medium to coarse textured foliage were not as aesthetically pleasing as mowed turf grass. Fine textured foliage looked better after mowing. The trial did not assess foot traffic which would occur in a home landscape. The top five top performers for this trial are:
- C. woodii (Wood’s Sedge): 4.9 shade, and 4.9 sun
- C. eburnea (bristle-leaf sedge) 4.6 shade, and 3.6 sun
- C. socialis (low woodland sedge) 2.4 shade, and 4.6 sun
- C. pensylvanica (Pennsylvania sedge) 4.3 shade, and 4.4 sun
- C. jamesii (James’s sedge) 4.0 shade, and 4.4 sun
As I mentioned before, my ‘Evergold’ is a brightly colored cultivar that I found in a local garden center. None of these native species mentioned in the report were at the center, nor have I seen them at any other local garden center. In fact, there are many native species but you may not find them at your nursery. So if this report has you salivating for these plants, you may want to try these nurseries below. Full disclosure: these were not listed in the report and do not imply endorsement by Mt. Cuba Center.
Also, if you are intrigued and want to learn more about carex plants, Sam Hoadley, who manages the Mt. Cuba Center’s Trial Garden and was responsible for this trial, will present Carex for Every Garden on February 1, 6 to 7:30 pm, virtually for a nominal fee. Register here.
Mt. Cuba Center is a destination garden, a public garden in Delaware that highlights the beauty and value of native plants to inspire conservation. I highly recommend visiting them and checking out their website for educational events and past reports on other plants.
All photos are courtesy of Mt. Cuba Center.