Sedges and rushes are not the most exciting plants in our bush, but they are an important part. These plants protect the soil from erosion and are important habitat plants for insects, spiders, larger animals, and birds. They become obvious on misty mornings when each one becomes a dewy spider palace. Before European settlement, these plants were habitat and food for numerous emus, small rodents and marsupials, which are locally extinct. Rushes and sedges are still important habitat in wetlands. Western Grey Kangaroos and even foxes nibble sedge leaves.
Tent web spider in Lepidosperma costale sedge in Foxes Lair
Phragmites australis flowering at Gnarojin Park I am writing this blog for myself because descriptions and common names for this group are confusing.
A commonly used rhyme to distinguish between grasses, sedges, and rushes is.
“Sedges (Cyperaceae) have edges, rushes (Juncaceae) are round, grasses (Poaceae) have knee joints all the way to the ground”.
This rhyme is not useful in WA.
Does it matter if you can't tell the difference? Occasionally yes when weeds are involved. A recent example was a decision to replace Bull Rushes in Narrogin Creek with Common Reed Phragmites Australis, which is an introduced weed. Phragmites is certainly impressive and probably isn’t a problem there apart from blocking the creek, but it kills adjoining plants and is an aggressive weed in coastal wetlands.
A commonly used rhyme to distinguish between grasses, sedges, and rushes is.
“Sedges (Cyperaceae) have edges, rushes (Juncaceae) are round, grasses (Poaceae) have knee joints all the way to the ground”.
This rhyme is not useful in WA.
Does it matter if you can't tell the difference? Occasionally yes when weeds are involved. A recent example was a decision to replace Bull Rushes in Narrogin Creek with Common Reed Phragmites Australis, which is an introduced weed. Phragmites is certainly impressive and probably isn’t a problem there apart from blocking the creek, but it kills adjoining plants and is an aggressive weed in coastal wetlands.
A narrow-leaved sedge Here are my local rules of thumb.
Grasses (Poaceae), sedges (Cyperaceae), rushes (Juncaceae) and southern rushes (Anarthriaceae and Restionaceae) are all wind pollinated monocotyledons, which grow as annuals or clumping perennials. Perennial plants spread by horizontal underground roots called rhizomes.
There are lots of native and introduced grasses around, which can be easily identified by their hollow stems and stem joints called nodes.
Grasses (Poaceae), sedges (Cyperaceae), rushes (Juncaceae) and southern rushes (Anarthriaceae and Restionaceae) are all wind pollinated monocotyledons, which grow as annuals or clumping perennials. Perennial plants spread by horizontal underground roots called rhizomes.
There are lots of native and introduced grasses around, which can be easily identified by their hollow stems and stem joints called nodes.
Typical grass features
Tasting result = blah Sedges and rushes don’t have nodes, usually have solid pithy stems, and their leaves arise from a rhizome near the ground. Wetland species commonly called rushes may actually be sedges or grasses. For example, Bull Rush or Cumbungi / Typha species are wetland grasses. Cumbungi is a bush tucker plant, which I decided to taste recently in the spirit of citizen science. Chewing a peeled rhizome was less than successful, so I cooked some in the microwave. Result: Texture = rope, taste = blah! Perhaps I should have collected my sample in the growing season and not from a roadside ditch. When I first came to Narrogin, Cumbungi groves formed wonderful bird nesting areas in Railway Dam. Our drying climate has almost eliminated them now.
 Bull Rush/Cumbungi Typha orientalis |  1991 Bull Rush grove at Railway Dam |  2023 same spot at Railway Dam |
Juncus acutus Railway Dam Locally, the classic round, smooth-leaved rushes are mostly weeds. Toad Rush Juncus bufonius is a tiny annual weed which was a problem in wet areas in crops before no-till farming.
Spiny Rush Juncus acutus is an introduced spiny weed, which infests our damp waterways and dams. Despite this it is useful for reducing erosion in wet salty areas, and as wildlife habitat.
Spiny Rush Juncus acutus is an introduced spiny weed, which infests our damp waterways and dams. Despite this it is useful for reducing erosion in wet salty areas, and as wildlife habitat.
Sedges may have flat or angled leaves (‘edges”) or not. I have noticed that flat-leaved species tend to be larger plants, which occur more often in winter wet/summer dry areas on slopes and flats. Flowers are often surrounded by spiky bracts and each produces a single small nut.
Broad-leaved sedge on winter-wet sand over clay valley at Quinns Block
 Lepidosperma tubercalatum |  Lepidosperma brunonium flowering July |  Narrow leaved Lepidosperma species |
Schoenus species are small narrow-leaved sedges. Ground-hugging Schoenus calcaratum would be a delightful addition to the native garden.
 Lawn-like Schoenus calcaratum |  Rhizomes and shoots |  Plant dries out over summer |
A special group In southwestern WA is called southern rushes. Unlike sedges and rushes, they are dioecious (have male and female plants). There are two families, Anarthriaceae (mainly near to the coast), and (local) Restionaceae.
Restionaceae are funky mat-like plants with round green to grey-green stems (culms),and brownish scale leaves, which often occur in patches in open kwongan or woodland. Being very tough plants which can withstand short-term waterlogging then drought, they are often found on open gravel, sand,or sand over clay.
Lepidobolus species have curly snake-like culms
Restionaceae are funky mat-like plants with round green to grey-green stems (culms),and brownish scale leaves, which often occur in patches in open kwongan or woodland. Being very tough plants which can withstand short-term waterlogging then drought, they are often found on open gravel, sand,or sand over clay.
Lepidobolus species have curly snake-like culms
 Lepidobolus chaetocephalus |  L. preissanus on riverside sand over clay flat |  Lepidobolus preissianus |
Desmocladus species have branched culms and female plants with leaf sheaths that sprout clusters of short stalks each with a single flower, which make them look like branched leaves.
 Female Desmocladus fasciculatus |  Male Desmocladus asper |  Hare orchids in a Desmocladus asper patch |