Grasses and Sedges

The Difference Between Grasses and Sedges :

As grasses, sedges, and rushes are often refered to as ‘ornamental grasses’ this is because they can all be used to provide a wide range of unique textures, with variying degress of movement, while adding to the surrounding architecture with their range of color and sound. Although they are often visable all year round in any landscape, the general rule is that the grasses prefer the sunny areas of the landscape with the well drained soils where as the sedge and rush often thrive in the most shady and moist locations available.

Grass/Rush can either be annuals or perennials, whereas all Sedges are perennial.
To identify these, the stems of both sedges and rushes are generally soild, where as the grass is hollow, and the stem, If you look closely, you can distinguish each from the other by structural differences as well as by general differences in their native habitat and distribution.

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Rush, any of several flowering plants distinguished by cylindrical stalks or hollow, stemlike leaves. They are found in temperate regions and particularly in moist or shady locations. The rush family (Juncaceae) includes Juncus, the common rushes, and Luzula, the woodrushes. Common rushes are used in many parts of the world for weaving into chair bottoms, mats, and basketwork, and the pith serves as wicks in open oil lamps and for tallow candles (rushlights). J. effusus, called soft rush, is used to make the tatami mats of Japan. The bulrush, also called reed mace and cattail, is Typha angustifolia, belonging to the family Typhaceae; its stems and leaves are used in North India for ropes, mats, and baskets. The horsetail genus (Equisetum) is called scouring rush, or Dutch rush, because the plants’ silica-laden stalks are used for scouring metal and other hard surfaces. Flowering rush is Butomus umbellatus (family Butomaceae). The sweet rush, or sweet flag, is Acorus calamus (family Acoraceae).

Soft rush (Juncus effusus)A to Z Botanical Collection/Encyclopædia Britannica, Inc.

“I want to point out that plants are something entirely different from animals. They are the true foundation of the larger life forms, necessary for something to have become of this planet. The plants had to do it first,and what strikes one so much is that, when the scientists or engineers say, ‘here in this water, animal life is dying’ they don’t even consider the plants — what plants are growing as a basis for animal life in water. Look at that picture near your bag — see the snowy white roots on those reeds? That was in a really awful brew of water in America, in South Carolina, where we did substance tests. It’s a small river in which the water had become so polluted the farmers could no longer let their stock drink its waters, and no one could find a solution. The hoses we laid actually disintegrated, yet the plants continued to grow! That is, plants have a completely different lifestyle than animals. And this is something still not understood. If you want to prepare things for animals to live, you must create a prior culture of plants.

“We have been testing and demonstrating this for many years, and no one else had done it before us. I came here with that intention — to show that waters must first be reconstituted with plants. And if this were understood and acted on wherever dirty effluents are poured into bodies of water, we would not have such problems today. Unfortunately, biologists have never adequately concerned themselves with plants. Even at our Max Planck Institute, there were wellknown chemists, zoologists, microbiologists, but no one concerned with plants. In fact, they laughed at me.”

At eighty-two, Dr. Kaethe Seidel, head of the former Limnology Group of the Max Planck Institute, long nicknamed Bulrush Kate (“Die Binzen Kaethe”), is a tough-minded, clear-thinking scientist with a remarkable record of pioneering work in a kind of biological wastewater treatment that should be far better known and used than is the case. In the course of a professional career spanning over sixty years, she has demonstrated the effectiveness of naturally growing plants in breaking down ballast substances, transposing toxic into non-toxic substances, destroying pathogenic bacteria, viruses and worm eggs, removing heavy metals, cleaning oil spills, removing salt, neutralizing pH, enriching with oxygen, transforming waste water into drinking water and replenishing groundwater — all with photosynthesis as the sole energy source.

Scientists from NASA, from Japan, from many institutes worldwide who have discovered her work have visited her to learn more, yet there is relatively little followup given its scope and importance except for the remarkable installations for which she has been more or less directly responsible.

“Why,” I asked her, as we sat in the huge old mansion that served as headquarters for the Limnology Group, in the midst of a nature preserve near Krefeld in Germany, where she now lives alone until her immanent eviction, due to sale of the property by the Max Planck Institute.

Her answer was telling. “Men always reach for technology, for development. They insist it will bring us to higher levels of progress. They haven’t the patience to work with slow-growing plants, nor do they understand natural cycles as women do. They see my work as farming, not engineering, so they go away and return to their machinery.”

“Wait till we run out of water,” I countered. “They’ll all come running to you then.”

I first heard Kaethe Seidel’s name mentioned by John Todd, founder of the New Alchemy Institute in Falmouth, Massachusetts and Ocean Arks International, with its more recent Center for Protection and Restoration of Waters. He had said she deserved a Nobel Prize for her lifelong work on what various plants take from their environment, and indicated that it had been important to his own work. I did not guess then how important, but noted that he mentioned her name again when we both gave keynote addresses at the Fifth Annual Conference of the International Institute for Advanced Studies in Cybernetics and Information Systems in Baden Baden. Something in me demanded I try to find her, so I set out to do so and within a week, I was talking with her.

The information contained in this article, other than direct quotes, can be found in the 1978 edition of her research report Contributions ti Revitalization of Waters (Stiftung Limnologisthe Arbeitsgruppe, Dr. Seidel e.V., Am Waldwinkel 70, D4150 Krefeld-Hulserberg, W. Germany), the only report of her work translated into English, though her publications number, in addition, 114 journal and book contributions and one entire volume, Limnologie in Stichworten, published by Erich Schmidt Veriag GmbH, Berlin.

The 1976 report states on p. 2 that “Kaethe Seidel aroused the opposition of experts in 1953,” when in a report from the Max Planck Institute, she discussed the possibility “of lessening the overfertilization, pollution and silting up of inland waters through appropriate plants, thereby allowing the contaminated waters to support life once more.”

One gets the impression that despite her long laboratory research record, her male colleagues have always regarded her an upstart whose elbows-in-the-dirt approach was somehow beneath the professional dignity of proper scientists. Nor did she work with exotic organisms, and one can imagine the blows to the pride of hi-tech engineers when she demonstrated that common reeds and bulrushes could easily do the job of elaborate waste water treatment plants.

Already in 1953, she suggested for this purpose the common bulrush, Schoenoplectus lacustris (L.) Palla (old designation Scirpus lacustris), having proved in her research work that this species was capable of “removing large quantities of organic and inorganic substances from contaminated waters.”

Until that time it had been assumed that higher flowering plants, including such rushes, could only exist in non-polluted waters, yet Seidel showed the astonishing adaptability of many plants to changing conditions of pollution, to wit, the remarkable green parks that continue in many industrial areas. By 1957, Seidel had shown that her bulrushes not only enrich the soil they grow in with bacteria and humus, but apparently exude antibiotics that kill mould fungi. She had also shown that they take up large quantities of ballast substances including cobalt, copper, nickel, and manganese from sewage water, and that other higher plants, including the common reed, Phragmites communis Trin., are capable of drying out and mineralizing assorted sludge combinations which are normally difficult to remove. The almost water-free residues contain very little, if any, dangerous bacteria or worm eggs.

Prior observations of natural waters had indicated that water was cleaner and fish healthier where rush populations existed. In the laboratory, it was shown clearly that an astonishingly fast alteration of bacterial populations occur in the region of the rushes, as well as of some higher plants. E. coli, coliform bacteria, salmonella, enterococci disappeared entirely within a day while healthy bacterial populations increased. These results were confirmed in 1966 by L. Althaus in a series of experiments at the Gelsenkirchen Hygiene Institute in Urach, which showed additionally that viruses and worm eggs were eliminated. Other studies showed that up to 90% of E. coli, enterococcus and salmonella organisms could be eliminated in as little as two hours by a number of other plants, including water mint (Mentha aquat.), water plantain (Alisma plan.), soft rush (Juncus eff.), yellow flag (Iris pseud.) and the bulrushes and reeds cited previously.

Other plants researched by the team include sunflowers, cattails, water hyacinths and various grasses. In 1963, Seidel’s Limnological Team established a cooperative effort with a large waterworks and several specialized institutes to test the effects of various plants on pathogen elimination, organic, inorganic and toxic substance uptake (including phenols, cyanate, thiocyanate), and differing origin sludge mineralization on wastewater from nuclear research centers, steel, food and pharmaceutical industries. After a promising start, the Limnological Team’s monies dried up, though at least fourteen other research centers in universities, municipalities and private institutes took up the research.

Challenges to the results on the removal from wastewater of hydrocarbons such as phenol and its derivatives were met when the metabolism of phenol in Schoenoplectus lacustris was worked out in detail by R. Kickuth of the Gottingen Institute for Soil Science, with whom Seidel had been publishing on this subject as early as 1951.

In a three-year experiment on phenol uptake, the phenol was repeatedly added to well water in regulated quantities up to 100mg/l, the rushes removed it completely at any season, though more rapidly in summer than midwinter. Interestingly, the rushes gained in biomass though no other nutrients were supplied, showing that the phenols were converted to biomass. Other highly toxic phenol derivatives such as p-cresol, xylol, hydroquinone, resorcin, pyrochatecol, pyrolgallol, B-hydroxypyrochatecol, pyridine, p-quinoline, 2.4.6 colidin, napthol, aniline, guaicol, phloroglucine and p-chlorophenol were applied in twice the lethal dosage for fish and not only were tolerated by the rushes, but entirely removed from the waters. Other experiments demonstrated the effective breakdown of highly toxic pentachlorophenol and of cyanogen compounds.

In South Carolina, Schoenoplectus rushes were used to treat wastewater from a fabric printing works printing 400 km of fabric daily. While the feeding pipe coupling sockets were destroyed by the corrosive wastewater after one year of use, the rushes were thriving, displaying 10 to 20 times more lush growth than those in a healthy Schleswig Holstein lake.

Successful projects abandoned

In 1959, the Krefeld Waterworks allowed its gravelpit recharge ponds, containing chlorinated and flocked Rhine River water laden with ballast and flavour substances, phenols and pathogenic germs, to be planted with 10,000 Schoenoplectus plants. Prior to the planting, the pondwater, intended to replenish groundwater, was blocked from doing so by the buildup of an impermeable layer formed in the subsoil. After planting, the incrustation ceased and the water conveyed to nearby wells was free of bacteria, phenols and other troublesome substances. This planted percolation lake was fully functional for thirteen years with an hourly flowthrough of 400 cubic meters. It was shut down due to a change in management.

Tar abrasion and oil in street rainwater runoff were similarly cleaned in the Ruhrgebiet, and it was demonstrated that expensive pipelines to conduct poisoned autobahn runoff to conventional sewage plants was both harmful (because of fermentation processes occurring in the air-excluding pipes) and unnecessary.

Over the years, Seidel’s team carried out successful experiments with waste waters and sludge from the production of pharmaceutical drugs, print and paint, tinned foods, margarine, sugar, sauerkraut factories and packing plants, as well as with a eucalyptus lumber mill in Brazil. “The results were absolutely positive, so that the usage of out biological-ecological methods appeared most promising.” Even laboratory sludges from the nuclear research centre in Karlsruhe were treated, “yielding a compost upon which radish, spinach and other vegetables were grown and utilized with the greatest success.” The weakly radioactive sludges had previously been stored in concrete basins where they could never dry out and various methods of extracting the water by technical means had failed. The common reed, which disrupts colloids so that they release their bound water, completely removed and cleared the water of harmful substances.

As Dr. Seidel told me, “Our plant cultures took up radioactivity and later there was no trace of it, it simply did not exist. It was eliminated into the air through the leaf stomata. Some plants accumulate radioactivity and only release it through the stomata when they die. The quantities released were so low that there is no danger to other organisms. Trees could be planted in radioactive soil to remove the dangerous materials and warnings could be posted not to cut them if they are of the accumulator variety.”

Other demonstrated effects of reeds and rushes are the neutralization of pH in a matter of hours to a few days, the removal of asbestos, removal of oil in sweet, brackish and saltwater, via easily transported planted basins whose surfaces retain the suspended materials and oils within 2-3 minutes, permitting clear water to flow away. Such basins have been in use for up to seven months without failing to clear 1000mg diesel fuel/l in water or sludge. They can easily be installed on wet docks or floats in harbors or lorried to accident sites.

Seidel’s team was rare and remarkable for its continual application of carefully controlled laboratory results in field tests, its return to laboratory work whenever field results were not entirely successful or raised new questions. Field tests and commercial or government installations were basically of two types: intensive and extensive.

In 1964, a patent was issued for “Intensive Plants” involving “a filter layer constructed from wire netting and planted with root forming plants…the roots providing for the permeability of the filter when a sludge layer is formed on the filter surface.” The root-forming plants listed in the patent were the bulrush, water mint, and calamus (whose Latin names are given above) “especially because of their bactericidal action.” To speed up the sludge deposition “aerator pipes could be laid over the grating, thus leading to an acceleration of the multiplication process of the microorganisms attached to the suspended solids.” The scheme was to let the plants grow exclusively from the nutritive substances dispersed in the wastewater washing their roots and to enhance the synergetic action of microorganisms and sludge flocculation by the introduction of air. The sludge could then be periodically sucked out from under the grating by appropriately placed soil funnels.

A demonstration plant was set up in Urach as part of the Friedr. Krupp wastewater treatment system, attaining extremely good results, even in winter, reaching a wastewater quality “not previously held possible.” The 1976 report goes on to say: “The plant was unfortunately sacrificed for the building of a health treatment center.”

Clean water and gainful harvests in one

While intensive plants have a runthrough time of only a few hours, large extensive plants function effectively at slower rates. In Holland, there are several such “plants” — extensive fields of rushes that completely clean all the wastewater from large camping sites, one near Elburg accommodating up to 6,000 people a day. The filtering effect of the planted soil remains constant despite the continuous supply of sludge and the installations pay for themselves by selling the harvested reeds as wicker material.

Bulrushes used to clean the wastewater from a sugar plant were periodically harvested and sold to fatten ducks, being excellent fodder also for cows and other stock. They are also a very fruitful loose compost, free of pathogenic germs, worm eggs or weed seeds, but containing useful bacteria. Where they have taken up heavy metals or toxins, they can be air dried and bundled for the well-paying international market for wicker. The common reed is similarly in demand as thatching and for matting. Such uses have paid for the harvesting machinery and labor in Dutch installations.

Bulrushes, having a single growth zone at the stem base (the intercalarcic meristem), can constantly grow out of an aggressive water or sludge zone along its entire height and can be harvested twice a year to keep them working. Reeds, on the other hand, have growth nodes all along the stem, so that aggressive substances accumulate in the lowest stem part, eventually destroying the plant, and thus reeds work best with non-aggressive sludges. Both plants must be harvested only above the lowest growth zone to avoid replanting. If reeds are not cut back, water deteriorates quickly and reeds retreat. While many other plants have proved more successful for specific tasks (e.g. yellow flag for salt removal), the reeds and rushes stand out for their total performance.

Seidel added, in our conversation, “Rushes can live well where there are tides, too. We have planted them successfully on saltsea shores, but they must be able to get air when the tide goes out, not be in salt water continually. They could be planted around the North Sea, for example. What could evolve from that? Or in the Sudan, where the goats are dying from water polluted with sewage. Had they planted rushes around those ponds, they could have cleaned the water.

“In the late seventies, I spent some time at Lake Titicaca in Peru, where these rushes grow profusely 5,000 meters above sea level. The surrounding area was barren, there is no farming. But the rushes are harvested as fodder, as well as for roofing and for boatbuilding. These rushes, unlike grains, can be repeatedly harvested without resowing, as they keep growing back. Men cut them in the water at the lake’s edges, women transport them to the livestock. They are the best nourishment for cows, pigs, horses — full of vitamins.

“They have a fascinating construction, growing like a very tall chimney from a growth zone only 2-3 millimeters thick near their base. That is, they grow from the bottom up. A chimney could never be built that way, but this plant can do it continually for years. You only must be careful not to cut into this growth zone when harvesting them.”

(Seidel’s early background, well before she won a doctorate, was as a trained master gardener and her team always emphasized the importance of careful cultivation and supervision in their working field installations to ensure their functions over long time periods, pointing out that other wastewater facilities must also be constantly monitored. Unfortunately, such installations were often not built to Seidel’s specifications and remained unattended in use. When such efforts failed, the technique itself was blamed.)

“I saw rushes planted not only at Lake Titicaca but in even higher ground, on outlying areas, in fields. If only this culture would be spread widely in the third world. I’ve been asked to come to Lake Baikal, but I don’t know yet whether something will come of it. I’ve been there once and the rushes would work well there; also in Africa. Wherever rushes grow around water holes, the water can be drunk. It is so clear. On the Ivory Coast, it is posted that one should drink only where there are rushes. But not much is being done with this knowledge.”

Understanding ecosystems

“Young people today study science, but have little practical experience and knowledge. Some landscape architects are interested in saving rivers now, but they don’t understand why they should plant rushes along their banks. Then there is the Adriatic problem, which could be attacked. But it seems we would rather proceed to catastrophe than become sensible.

“Young people who care tend to focus on animals. The big thing nowadays in Germany is biotopes, biotopes. And what they are doing is dangerous. They are creating artificial ponds, planting them so they will attract birds and dragonflies. But they are also attracting mosquitoes that spread diseases. It is a fashion now in Germany to create these biotopes. New groundwater is pumped up to create the ponds and is blown off and evaporated into the atmosphere. Rather than reclaiming water already above ground, they reduce the groundwater even more! Plants get their own water from the ground and do not waste it.

“If you think about what is being done, in agriculture, in wastewater treatment, it is hard to maintain sanity. We showed in Krefeld (see above) that water pumped from the middle of the Rhine, passed through a simple filter and then poured through a field of these rushes could be put directly into water pipes without further treatment — pure drinking water. But men do not pursue these methods because they do not demand technology and thus do not make profits. Nor do they want to do the plantings; they say they are engineers, not farmers.

“In Brazil, we demonstrated that the hot and highly acid wastewater from a eucalyptus sawmill could be recycled through plants. We could not find the reeds there, but found other plants that also work. There is so much that can be done. All normal wastewater from human habitation can easily be directed into small streams planted with rushes or reeds and reclaimed at least for agriculture. Pathogenic bacteria are so quickly and easily destroyed…”

It is apparently Seidel’s patented intensive system which has been adapted by John Todd in New England (Vermont and Rhode Island), though when I told her the plants there are contained in greenhouses, she was puzzled, as her own installations have not required housing even under winter conditions. “Rushes work summer and winter, around the clock, even under two meters of snow,” she told me. All that is required to make the intensive system work is to isolate the reed basins from surrounding soil.

These basins contain drainage pipes in course gravel at the bottom, fine gravel planted with reeds or rushes above, topped by a few centimeters of fine filtering sand. Contaminated water is fed in from above. A series of such basins are cascaded to aerate the water. For the sludge load of typical sewage water, 1 square meter of reed basin (w. 20 rush or reed plants) serves 1 cubic meter of contaminated water per day.

Perhaps Todd has found that the more complex technology of his “living machines” improves the efficiency of the plants, but it is also important to spread information on simple projects people can implement without financial investment in areas where financial resources are lacking.

The more complex such natural water-cleaning systems become and the more difficult they are to construct and maintain, the less accessible they will be to ordinary people around the world. Bulrush Kate seems more in tune with thousands of years of pre-industrial agriculture in which people met their needs by learning nature’s creative ways to create their own productive nonpolluting ecosystems without ever seeing their work as engineered miracles. These methods remain appropriate in many areas of the world today.



a sedge of species Carex halleriana


  • IPA(key): /sɛd͡ʒ/
  • Rhymes: -ɛdʒ
  • Audio (UK) (file)

Etymology 1

From Middle English segge, from Old English seċġ, from Proto-Germanic *sagjaz, from Proto-Indo-European *sak- (“marsh plant”). Cognate with Dutch zegge and German Segge, dialectal German Saher ‘reeds’.


sedge (plural sedges)

English Wikipedia has an article on: Wikipedia

  1. Any plant of the genus Carex, the true sedges, perennial, endogenous herbs, often growing in dense tufts in marshy places. They have triangular jointless stems, a spiked inflorescence, and long grasslike leaves which are usually rough on the margins and midrib. There are several hundred species.
    • 1907, Robert William Chambers, chapter VIII, in The Younger Set, New York, N.Y.: D. Appleton & Company, OCLC 24962326: But when the moon rose and the breeze awakened, and the sedges stirred, and the cat’s-paws raced across the moonlit ponds, and the far surf off Wonder Head intoned the hymn of the four winds, the trinity, earth and sky and water, became one thunderous symphony—a harmony of sound and colour silvered to a monochrome by the moon.
  2. Any plant of the family Cyperaceae.
Derived terms
  • sedged
  • sedge fly
  • sedge frog

any plant of the genus Carex any plant of the family Cyperaceae

  • Finnish: sarakasvi (fi)

See also
  • bulrush
  • reed
  • sedge on Wikipedia.Wikipedia
  • Carex on Wikispecies.Wikispecies

Etymology 2

By contraction from sedge fly.

sedge (plural sedges)

  1. (fishing) A dry fly used in fly fishing, designed to resemble a sedge or caddis fly.

Etymology 3

Variant spellings.

sedge (plural sedges)

  1. Obsolete spelling of siege
  2. Alternative spelling of segge
  3. A flock of herons, cranes, or bitterns.


  • edges

What is a Sedge?

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Sedges are a group of plants which form clumps, mounds, or tussocks: they have long, narrow leaves and are often evergreen. Some of them are merely ankle height, many of them are knee height, and some can even grow to waist height. They are particularly useful in situations with poor soil, as they are remarkably tough and establish themselves well, often being capable of spreading quite extensively.

Most Sedges will grow almost anywhere, but they particularly like damp soils, and indeed there are several Sedges which are perfect for waterlogged soil, and which can often provide dramatic water-side foliage.

Although technically they are flowering plants, the “flowers” are quite insignificant, so they are mostly grown just for their foliage: but those insignificant flowers produce large quantities of seeds, allowing these plants to spread widely, as well as extending their clumps from creeping underground rhizomes.

The botanical name for the true Sedge is Carex, and they are monocotyledons, which means that they are flowering plants whose embryonic seeds only have one cotyledon or leaf: most of what we think of as “flowering plants” are dicotyledons, with two of these seed-leaves. It’s a tiny distinction, but extremely important as it is one of the most basic classifications.

In gardening terms, most monocotyledons have long, thin, strap-like leaves in which the veins run parallel to the long sides, instead of the familiar branching net of veins which we see in the dicotyledons. Monocots include, in addition to Sedges, the similar-looking Grasses and Rushes, plants such as Lilies, Bamboo, and Onions, and many of our flowing bulbs such as Tulips, Daffodils, and Iris.

What are Sedges used for?
The 34 species of Carex in our Plant Finder include something for everyone, from glossy green leaves through stripy variegated foliage, right into foliage of bronze and red: and the leaves themselves are everything from the wide, soft leaves of Carex elata (Bowles’ golden sedge), through the broad, tough, centrally-ridged leaves of Carex siderosticha (the rather unimaginatively-titled Broad-leaved sedge), to the narrow hard hair-like leaves of Carex buchananii (Leatherleaf sedge). They are deservedly popular with horticulturalists as many of them will grow happily in shade, filling awkward corners and acting as ground cover to prevent the establishment of unwanted weeds: and despite looking like grass, they are rarely troubled by browsing deer or bunnies.

These properties make them very useful for erosion control, on hillsides as well as in waterside areas.

They are perennial plants, so they come back year after year, and many of them are evergreen, although a lot of the bronze-foliaged types can turn a less-attractive brown colour in a mild, damp winter: a cold winter will keep them crisp and sharp looking, and they can look fabulous when rimmed with frost. They are very easy-care plants: if they start to look a little tatty in spring, all you have to do is shear off the old foliage and they will quickly re-grow with fresh new leaves.

One of the most frequent plantings in the UK is Carex pendula, aptly known as Pendulous sedge, whose fat, catkin-like flowers dangle at the end of long hard stalks in early summer. They establish themselves well in a damp or pond-side environment, but will seed themselves happily all through the garden – in fact, they seed so prolifically that this particular Sedge is now often found growing in the wild.

In contemporary gardening, Sedges are most often found situated in pots, where their foliage can spill gracefully over the sides, and can either provide an interesting backdrop to flowering plants, or indeed can be appreciated in their own right.

Historically, Sedge has been used as a weaving material in countries such as Korea: mats, baskets and decorative items are woven from bleached Sedge leaves and have been, in their time, highly prized items. Also, several different species of Sedge have been identified as being used in footwear, as an insulating layer: a testament to the fact that Sedges will grow as far north as Scandinavia.

The Sedge in popular culture

Sedges are strangely absent from modern culture, but 4,000 years ago, the Sedge was the symbol for Lower Egypt, while the bee stood for Upper Egypt: in modern times, however, its influence has been reduced to the name of a brand of handwash.

How do you know it’s a Sedge?
When looking at a clump of something green and grass-like, you might be confused as to whether they are Sedges, Grasses or Rushes: it’s a difficult group. The first rule is “Sedges have Edges”. The flowering stems are triangular in cross-section, so each one will have three distinct corners or edges, and if you cut one across, you can clearly see this. Alternatively, to avoid damaging the plant just to identify it, you can try to roll a stem between your finger and thumb: if it won’t roll easily, then it is a Sedge.

There is a simple mnemonic which is useful when looking at “things that look like grass” and it goes like this:

Sedges Have Edges, Rushes are Round: Grasses are hollow, So which have you found?

Like all mnemonics, nothing is ever quite that simple, but it is a very good place to start!

There are not many plants called Sedge that are not proper Carex: one notable one is Uncinia or Red Hook Sedge, a low-growing plant which has amazingly red foliage all year round.

There is also the similar-sounding but utterly different-looking Ursinia: they are half-hardy plants with pinnate, fern-like foliage and bright, daisy-like flowers and are commonly known as Hook Sedge or, more appropriately, Jewel of the veldt.

Acorus gramineus is known as Dwarf sedge (or Japanese rush, or Japanese sweet flag) and it has curved, rigid glossy green leaves, forming low clumps of foliage in wetlands and shallow water: it can spread aggressively, making it a good ground cover plant.

Less aggressive is Acorus calamus or Murtle sedge, which is commonly grown as an aquatic, or bog plant. The roots have been used in the past for perfume, medicinally and as a food, as substitutes for cinnamon, nutmeg and ginger: but today, it is better to be safe, and to buy your medicine and spices from approved sources, and to just appreciate this as a garden plant.

And finally, returning to Carex, we have the aptly-named Mace sedge (Carex grayi) whose flowers are quite uninteresting, but which forms intricate inflated seed-pods, which look just like miniature versions of those spiked balls which were spun, on a short length of chain, in medieval times. They look quite murderous, but luckily they are only 1” (2.5cm) across!


Types: show 15 types… hide 15 types… Cyperus alternifolius, umbrella plant, umbrella sedge African sedge widely cultivated as an ornamental water plant for its terminal umbrellalike cluster of slender grasslike leaves Cyperus esculentus, chufa, earth almond, ground almond, rush nut, yellow nutgrass European sedge having small edible nutlike tubers Cyperus longus, galangal, galingale European sedge having rough-edged leaves and spikelets of reddish flowers and aromatic roots Cyperus papyrus, Egyptian paper reed, Egyptian paper rush, paper plant, paper rush, papyrus tall sedge of the Nile valley yielding fiber that served many purposes in historic times Cyperus rotundus, nut grass, nut sedge, nutgrass, nutsedge a widely distributed perennial sedge having small edible nutlike tubers Carex arenaria, sand reed, sand sedge European maritime sedge naturalized along Atlantic coast of United States; rootstock has properties of sarsaparilla Carex pseudocyperus, cypress sedge tufted sedge of temperate regions; nearly cosmopolitan cotton grass, cotton rush any sedge of the genus Eriophorum; north temperate bog plants with tufted spikes Scirpus acutus, hardstem bulrush, hardstemmed bulrush widely distributed North American sedge having rigid olive green stems Scirpus cyperinus, wool grass sedge of eastern North America having numerous clustered woolly spikelets spike rush a sedge of the genus Eleocharis Eriophorum angustifolium, common cotton grass having densely tufted white cottony or downlike glumes Chinese water chestnut, Eleocharis dulcis, water chestnut Chinese sedge yielding edible bulb-shaped tubers Eleocharis acicularis, hair grass, needle rush, needle spike rush, slender spike rush fine-leaved aquatic spike rush; popular as aerator for aquariums Eleocharis palustris, creeping spike rush cylindrical-stemmed sedge Type of: bog plant, marsh plant, swamp plant a semiaquatic plant that grows in soft wet land; most are monocots: sedge, sphagnum, grasses, cattails, etc; possibly heath

Sedges and Grasses

Posted in Gardening Tips on November 22 2011, by Sonia Uyterhoeven

A few weeks ago, I was displaying some grasses and sedges for a home gardening demonstration when a woman asked me what the difference is between the two. Naturally, there are anatomical and sometimes cultural differences (always generalizations) between these similar plants, however, they are often categorized together and thought of as the same. To help clarify the differences, we will begin with a useful mnemonic:

Sedges have edges,
Rushes are round,
Grasses have nodes from the top to the ground.

Grasses and bamboos are in the Graminaceae family, sedges are in the Cyperaceae family, and rushes are in the Juncaceae family. When you look at a grass or sedge, what you see are the stems, leaves, and flowers. And in the case of this explanation, the stems are referred to as culms.

Explaining that earlier bit of verse requires some plant anatomy, however. In grasses, the culms are cylindrical and covered in nodes (swollen joints); if you were to cut open a grass or bamboo, you would notice that the culms are hollow, and the nodes are solid. But with sedges–which have no nodes–it is the culms themselves that are solid (not to mention triangular). And finally, rushes are round like grasses, but are similar to sedges in that they have solid culms and an absence of nodes. This can all be somewhat difficult to remember, but the mnemonic above should make more sense to you now.

Out of the three families, the ornamental grasses have the showiest flowers. The inflorescence–or flowering part–is sometimes shaped as a collection of showy plumes, bottlebrush spikes, oat-like seed heads or silky, hair-like structures called awns.

If you visit the Home Gardening Center any time from August into November, you will undoubtedly find the warm season ornamental grasses stealing the show with their billowy blooms. One that takes almost everyone by surprise is the pink muhly grass (Muhlenbergia capillaris), with airy panicles that create a rich, pink haze. We also grow an annual fountain grass (Pennisetum setaceum ‘Burgundy Giant’) that has a deep burgundy color and large racemes (an inflorescence where the flowers are attached to the stem by short stalks) that look like fuzzy bottle brushes.

Carex albula ‘Frosted Curls’ — A Sedge Ideal for Shade Gardens

Many of the fountain grasses’ flowering structures make wonderful additions to late season flower arrangements. However, we have taken most of the hardy fountain grasses out of the garden because of their habit of seeding around in places they’re not welcome, and instead content ourselves with a wide selection of annual fountain grasses.

For those looking to add to their gardens, the majority of ornamental grasses thrive in full sun and can handle drought magnificently. During the dry summers they are very little work, and taller varieties don’t often require staking. Wet summers are a different story, though, where staking is a requisite.

Because of their beautiful flowering structures, ornamental grasses are by far the most popular for gardeners, though sedges hold a special place in the hearts of those who prefer shade gardening. Most sedges tolerate shade better than grasses and–depending on the species–they handle a wide range of soils from wet to dry. Carex pensylvanica, sometimes referred to as Pennsylvania or oak sedge, is an ideal lawn substitute or ground cover for a shady spot. It has a fine texture and a graceful fountain habit that spills over the ground.

And if you are looking for something with broader leaves, Carex ‘Ice Dance’ has wonderfully variegated foliage. In our case, we had a bare, shady slope on the edge of the garden that was a breeding ground for weeds and washouts after every rainstorm. Two years ago we decided to cover the bank with small plugs of Carex, and it has since begun filling in nicely to provide a remedy to our problems.

Another feature that I appreciate about ‘Ice Dance’ is its flexibility. If I am running behind schedule in the spring and I forget to cut back its winter growth, it doesn’t seem to mind; the new growth covers the old and within a month it is looking just as perky as it was in the previous season.

Hakonechloa macra ‘Aureola’ — Japanese Forest Grass

Try to keep in mind that while sedges generally handle shade better than grasses, there are always exceptions to these generalizations; there is a whole host of sedges that thrive in full sun. And if you’re looking for something ideal in the grass family, one of the most versatile options for the shade garden is the Japanese forest grass (Hakonechloa macra).

When choosing a grass or sedge, educate yourself on its size and shape before you incorporate it into your garden. Decide whether you are growing it just for the foliage or for the flower, as well. Small sedges and grasses make wonderful edging for a border, while larger grasses are fantastic focal points that make strong statements. Grasses and sedges can also make nice backdrops for other plants. They are ideal for naturalistic, wildlife-friendly, low-maintenance, or sophisticated designs, and are also suitable for container plantings.

If you have been involved in growing them or are simply interested, what are your favorite grasses or sedges?

Features of the Order Graminales

  • The flowers are inconspicuous, are arranged in spikelets and enclosed in chaffey (papery) scales. They do not have petals and sepals (image of a grass flowering head here).
  • The fruit is one seeded. Its seed coat is united with the ovary wall and is called a Caryopsis.

Grasses are in the Family Poaceae, (also known as Gramineae), and Sedges are in the Family Cyperaceae.

The main differences are:



Cylindrical, usually hollow stems.

Triangular, solid stems.

Alternate leaves, in 2 ranks.

Leaves in 3 ranks.

Flowers have 3 types of bracts.

Flowers have a single type of bract.

The Rushes are in the order Liliales and have many similar features to Lily flowers, except that the petals and sepals are small, brown and scale-like and are called tepals. (They are called tepals collectively, because the sepals and petals look exactly the same and are indistinguishable from each other.) Rushes belong to the Family Juncaceae. The main features of this family are:

  • Each flower is composed of 2 rings of tepals.
  • Inside the perianth (the rings of tepals) are one or two rings of 3 stamens.
  • In the centre is the ovary with 3 stigmas.
  • The fruit is a capsule.

(General flower structure in flowering plants here)

There are 2 genera of rushes in Britain, (in contrast to the 54 genera of grasses).

Luzula (Woodrushes) which have hairy, grass- like leaves and 3 seeded capsules (left).

Juncus (Rushes) which have hairless, cylindrical stem-like leaves and many seeded capsules (right).

Continue to

Grass Structure

Glumiflorae: More on Morphology

One feature that has contributed to the success of the Glumiflorae is their ability to spread vegetatively by creeping stems. Unlike trees and most herbs, the Glumiflorae have a primary stem that grows along the surface of the ground, or even underground as in bamboo. Branches or leaves are then sent upwards to gather light for photosynthesis. It is this “sideways” growth of the stem that keeps grass growing even after being mowed.

Leaves are usually attached to the stem in two rows, running along each side, except in many sedges. The triangular arrangement of the leaves in sedges is actually a very good character for recognizing them. This has given rise to the saying:

      Sedges have edges, and rushes are round,
      But grasses have nodes from their tips to the ground.

The “edges” are there because of the way the leaves meet each other along their edges, while the “round” rushes usually have one leaf sheathing the stem. “Nodes” are swollen regions of the stem, where leaves are attached, and can be felt by running your hand along the stem. Of course this saying assumes that you can recognize cattails, bur-reeds, and other Glumiflorae; it is the rushes, sedges, and grasses that are most easily confused.

In the Glumiflorae, the leaf bases are wrapped tightly around the stem, often obscuring the stem completely as the leaves overlap. There may also be silica in the leaf epidermis making it feel rough, probably an adaptation to deter herbivores. If you ever have the chance to look closely at a corn stalk, you can see all these features.

Members of the Glumiflorae are anemophilous, or “wind-loving.” This term refers to the way in which these plants are pollinated. Rather than relying on insects or birds to carry their pollen, graminoids make use of the wind. This reliance on wind pollination is probably responsible for the loss of petals and sepals in members of this group. That’s right! Grasses, rushes, and sedges all produce flowers that must be pollinated for sexual reproduction to occur. If you are surprised by this, don’t feel bad, most people have never gotten a close enough look at these plants to see their flowers, and besides, they don’t have showy petals. In fact, many species have no petals at all; their flowers are simply anthers and pistil.

In the picture at right, you can see a closeup of the flowers of Paspalum, a grass. The fuzzy black hairs are the tips of the pistil (the stigma); these hairs are sticky, and help the flowers to capture the pollen. Cornsilk is also a collection of stigmata, and each thread of the cornsilk connects to a flower with an ovule.

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