Basic information about Carex. Includes Origin, Growing & Cultivation, Common Pests & Diseases, Interesting Facts & Uses, and Garden Design Tips.
The botanical name, Carex, was established by Linnaeus in his Species Plantarum in 1753. It comes from the Greek word ‘kerio’, meaning ‘to cut’. Sedges have tiny, saw-toothed edges; handle carefully!
The common name, Sedge, is derived from the Latin word, ‘secare’, also meaning ‘to cut’. People took this attribute very seriously!
Carex are native to most of the world, with fewer species occurring in Africa. They are mostly found in various types of wetlands, and are one of the dominant plant groups in arctic and alpine tundra.
Growing and Cultivation
Carex is a huge genus with hundreds of species. The species HostasDirect offers are varieties selected for shade. C. oshimensis and C. phyllocephala prefer partial shade and well-draining but rich soil. Most Carex spread slowly, if at all, through underground rhizomes. They enjoy a light slow-release fertilizer or soil amendment at planting, but do not require feeding after that. Carex can tolerate dry shade, only requiring watering once a month; in periods of severe drought, water twice a month. May go dormant in hot and dry conditions; to prevent make sure to water in drought conditions. You may shear plants after they bloom to keep them tidy, or choose to leave them alone. After a few years, they can die out in the center; this can be remedied by dividing the plant and replanting a division for renewed vigor.
Common Pests and Diseases
The most common disease shown to attack Carex is Rust. Occasionally fungal or bacterial leaf spot can appear, or aphids arrive to eat leaves, but these are less common.
Rust is usually noticed at the point of no return: the spore sacs (on the undersides of leaves) have burst, releasing clouds of fuzzy-looking bright orange spores. Any foliage affected should be immediately and carefully removed and disposed of (do NOT put in a compost pile!). It can also be treated with copper sprays and sulfur powders, but they must be applied weekly and work slowly. Removal of affected parts quickly as they develop (especially if you can catch it before white sacs have burst into orange spores) is the most effective way to eradicate it.
Here are some pictures of plant rust:
Interesting Facts and Uses
Carex are not grasses! Carex is one of the largest genera of flowering plants, with an estimated 1,100 to 2,000 species. Their chromosome evolution is the most dynamic of all flowering plants, with a range of 6 to 66 pairs each.
A mixture of Carex species have been used historically as insulation in footwear by Sami (an indigenous people of northern Europe) as well as by the first human expedition to the South Pole in 1911.
Carex produce tiny seeds that feed many bird species, as well as foliage used by birds and other animals to line and create nests. Some species are also used as a livestock hay.
This plant has its own field of study, called caricology; the study of Carex, the “true” sedges.
There is a botanical rhyme designed to help identify if a plant is a sedge, grass, or rush:
“Sedges have edges and rushes are round, grasses are hollow and rush all around.”
While not always true, this is accurate the majority of the time.
Garden Design Tips
Carex works wonderfully as edging by walkways, contrasting backdrops for smaller plants or mixed into border plantings. Can also be massed as a ground cover in dry shade areas. Carex complements large-leaved plants such as hosta and bergenia, as well as purple, pink or blue colors (and share conditions with Fuchsias).
To purchase Carex varieties, please visit our Shade Companion Plants Page.