Many sedges flower, set seeds in early summer

By Bev Johnson

Master Gardener

If you like ornamental grasses, you will most probably like sedges. Unlike grasses that don’t flower until late in the season, many sedges flower and set seeds in May and June. This gives the gardener some early season interest in the garden.

The proper name for sedges is carex.  In order to properly identify sedges, you need to understand a few terms related to their fruiting structures. These terms aren’t going to come up in your usual gardening conversation so, take a deep breath. Here we go. Carex fruits that contain seeds are called achenes and are enclosed in a bladder-like sac called a perigynium. The shape of this structure is how one tells which sedge you are dealing with. Most carex species have separate male and female flowers. The actual sedge flowers aren’t very showy. It’s the fruiting structures containing the seeds that are ornamental. Unlike grasses, many sedges like to grow in the shade. 

Carex crinite, aka fringed sedge has pretty foliage. This sedge grows to about 30 inches tall and is chartreuse when grown in the sun. It has wider leaves than most other sedges, up to ½ inch wide. When it’s not blooming it looks like a daylily. The fruiting structure looks like a droopy caterpillar thus the nickname, caterpillar sedge.

Carex typhine grows about 2 feet tall. The 3/8-inch-wide foliage is lime green to yellow in both sun and shade. It may be greener in some soils. It does best in part shade as the leaves will burn in full sun. This sedge is native to wet woods and prairies. Use this plant in sunny rain gardens. The fruiting structure is the highlight of this plant. It has ¼ inch spikes composed of pointed penigynia arranged in a cylindrical spike. As this structure turns from green to brown it looks like it is covered in tiny cattails. These structures persist from June through October, truly a plant with full season interest. 

Carex lupuina, or hop sedge. This sedge has an odd-looking fruiting structure that looks much like hops when it appears in June. The ½ to 3/8-inch pointed penigynia radiate from the stem in a star-like pattern. Two or three of the clusters stick out from the flower. They persist all summer. This plant is about 2 feet tall with light to medium green foliage. The plant is slow to grow in the spring. It does best in moist shade as it is native to wet woods. 

Carex sprengelii, long beaked sedge. This sedge blooms in mid-May and produces pendulous fruiting clumps. The long beaked penigynia give this species its common name. The prigynia dries up by the end of June. This plant has ¼ inch wide leaves and is two feet tall and about 30 inches wide. It is commonly found In maple groves and does best in shade.

Our last carex, carex aurea can be a stinker. It has rhizomes and will spread if not kept in check. It is best used as a ground cover.  It is only about a foot tall and grows into 30-inch-wide clumps. The prigynia turn from green to yellowish orange as they mature and look like miniature grapes. The foliage is fine textured. It is described as being “more vigorous” in the sun if watered well. In other words, it probably heads for Mexico as soon as it gets well established. It is native to Northern Minnesota so will grow quite well here.