Wednesday, July 15, 2009

Carex Sedge: A Ground Cover Solution For Moist Soil

Carex hachijoensis 'Evergold'Carex is of the Cyperaceae, or sedge, family that contains at least 3000 species and 100 genera of grass-like perennials. As such, there is some confusion and misspelling about the specific names of many plants. Regardless, the one you end up with in your garden will certainly be lovely and virtually care free. Carex is found worldwide, is native to the U.S. and is most common in temperate and cold regions.

Carex is also called Sedge Grass and Japanese Sedge. It is frequently referred to as a tufted grass, a category that includes grasses, sedges, rushes and bamboos. Sedges are distinguished from grasses by their solid, three sided flower stems (grass flowers have round, hollow stems) and they typically form dense, compact clumps. For you botanists turned poets, you can distinguish them using this poem by an unknown author: “Sedges have edges and rushes are round, grasses are hollow and rush all around.” If you don’t want to remember that, just keep in mind that any plant from the genus Carex is a true sedge.

If you see a clump of “grass” growing in shady standing water, chances are it is Carex. Hardy in Zones 5-9, this ornamental grows in wet to very moist soils but prefers evenly moist, well drained, loamy, sandy or clay soils. It may tolerate shallow standing water for awhile. If the soil dries out it will begin to suffer from drought stress. The pH preference is neutral (7.0).

Carex will grow in full sun, but prefers partial to full shade. Consider your location before planting; if you live north of Maryland, full sun might be okay, but you won’t get away with full sun in Alabama. You’ll have to experiment and see how it performs in your garden.

Carex grows 6" high or more depending on the cultivar, and has dense tufts of fine, narrow, arching leaves. The 1" leaves are all shades of green with an abundance of variegations, and considering everything I just said above, have the best color in full sun. Its dense mounds make it difficult for weeds to survive. Carex is great for borders, containers, ground cover, rock gardens and water gardens. In well-drained gardens, Carex hides yellowing foliage of spring-flowering bulbs very well.

Sedges are easy to care for because they have no serious pests or diseases. The most you’ll have to do is divide it every few years because it spreads aggressively by rhizomes (but isn’t invasive). Propagation from division is best done in the spring. You can fertilize Carex as you see fit, but keep granular fertilizers off foliage and away from stems and crowns. I’d use half the recommended dose of fertilizer for new plantings, if at all. It remains lush all year round and there is no need to prune it. You’ll probably have to pull away some dead leaves in the winter, but you won’t have to spend additional time mulching it.

Interest in grasses and sedges has increased lately and I’m listing the three varieties of sedges about which I get the most inquiries.

Carex conica 'Hime Kansugi': One of the shortest Carex, it grows between 6" - 12” tall and 8" -10” wide. This dwarf variegated plant of green and white grows in sun or shade in Zones 5-9. Plant them 8" apart for an immediate full, dense look.

C. hachijoensis 'Evergold': Peaks at 8" - 12" tall, but has a wide spread up to 18”. This evergreen variety is very popular because of its slow growing and mounding habits as it spreads. Very nice green and yellow striped one-half inch wide leaves. Grows in Zones 6-9 and must have well-drained most soil. Great as a ground cover, but needs to be divided every few years to keep it tall and thick.

Carex morrowii 'Ice Dance': Grows 12” tall and 18” wide in sun or shade. It has green one-half inch wide leaves with white edges. Lives in Zones 5-9 and should be planted 18” apart. Lights up a shady spot well. This variety is very aggressive and is probably best suited for a container or ground cover.

Carex sedges are becoming more popular because they’re easy to take care of, gorgeous, and often the most colorful plant in the winter garden. If planted in moist to soggy areas in sun or shade they’ll do well and won’t need additional maintenance.

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