Identification of Sedge and Sedge-Like Weeds in Florida Citrus1
Sedges are annual or mostly perennial grass-like plants with aerial flower-bearing stems. In annual forms, the stem is solitary to mostly several with basal leaves. Perennial forms have a thick rootstock or an erect to horizontal underground rhizome usually with shortened internodes.
Sedges usually have triangular stems with leaves arranged in groups of three and are similar to grasses in many attributes. Sedge species may be found in a wide range of conditions, ranging from very wet to dry and in many soil types.
In sedges, as well as grasses, the seed head will be produced at the end of an aerial, erect stem. This three-sided stem is usually solitary and will be tufted with basal leaves. Root systems are fibrous, including species such as yellow and purple nutsedge which produce rhizomes and tubers. Flowers are extremely small and numerous and arranged in spikelets atop the stem.
Sedges are of little economic value to man but can be very competitive with the desired crop for water, nutrients and space.
Sedges
Yellow Nut Sedge (Cyperus esculentus)
Season: rapidly spreading, aggressive, erect perennial
Stem: slender, smooth, pithy and 3-angled (triangular in cross section), arising from rhizomes, tubers or basal bulbs
Height: up to 24 inches tall
Roots: fibrous, branched, with tubers on rhizomes
Leaf blade: yellowish green, prominent midvein, flat or slightly corrugated, 0.2 to 0.5 inch wide, waxy or shiny appearance, 3-ranked and growing from basal bulb, leaves usually as long or longer than flowering stem, blade tapering to long thin tip
Seed head: short, subtending leaf-like bracts, flattened, yellowish-brown spikelets, clustered around the ends of a few to 10 branches of unequal length
Propagated by: seeds, creeping rootstock (rhizomes), or small underground nutlets. Nutlets (tubers) are brown, round, lack hairs, 0.5 to 0.75 inch long and may lie dormant in soil several years. Nutlets are individually produced and sweet or neutral to taste.
Comments: prefers moist to dry cultivated soils and does not tolerate shade
Purple Nut Sedge (Cyperus rotundus)
Season: rapidly spreading, aggressive, erect perennial
Stem: erect, smooth, solid, triangular in cross section, arising from tuber or basal bulb, and usually longer than leaves
Height: up to 1.5 feet high
Roots: extensively branched, fibrous, with tubers on rhizomes
Leaf blade: deep-green, originates from the base of the plant, 3-ranked and grass-like, flat or slightly corrugated, prominent mid vein, 1/8 to 1/3 inch wide, and abruptly tapering to sharp point. Leaf is dark green, smooth, shiny, and usually shorter than stem.
Seed head: short subtending leaf-like bracts, numerous, flattened, red to purple brown spikelets clustered at the end of the stalk on a few to several branches
Propagated by: slender creeping rootstocks (rhizomes) and nutlets (tubers). Nutlets are covered with hairs and are bitter to the taste. Multiple nutlets are produced forming a tuber chain.
Comments: thrives in moist sandy soils but does not tolerate shade, often thought to be the world's worst weed
Green Kyllinga (Kyllinga brevifolia (Cyperus brevifolius))
Season: mat-forming perennial
Stem: dark green, arising from purple rhizomes, with 3 subtending leaves on the end of the flower stalk
Height: up to 18 inches tall, frequently about 6 inches tall
Roots: fibrous
Leaf blade: dark green, 1 to 5 inches long and narrow
Flower stalk: triangular in cross section
Seed head: subtended by a few leaf-like bracts, usually one, occasionally 2 or 3 heads, initially pale green and often turning brown at maturity, globe-shaped and 1/4 inch in diameter
Seed: oval, flat in cross section (1/16 inch long)
Propagated by: seeds and rhizomes
Comments: found in low areas where moisture is excessive, can form large mats
Annual Sedge, Watergrass (Cyperus compressus)
Season: annual
Stem: green, smooth
Height: 4 to 18 inches tall
Roots: reddish, fibrous, extensively branching, lacks rhizomes
Leaf blade: basal, 3-ranked, elongated and narrow (0.1 inch wide) and usually equal to or shorter than stem
Seed head: few to several, flat, greenish, spikelets at end of stem
Seed: dull brown, 3-sided, 1/16 inch long at maturity
Propagated by: seeds
Comments: found in sandy, moist soils, can form large tangled masses
Cylindric Sedge (Cyperus retrorsus)
Season: erect perennial
Stem: densely tufted
Height: up to 20 inches tall
Roots: fibrous, may form short rhizomes
Leaf blade: bright green, flat, smooth
Seed head: with 3-7 leaf-like bracts at top of stem, few to several branches of tight cylindrical clustered spikelets, green and turning brown to black at maturity
Propagated by: seeds and the very short rhizomes
Comments: grass-like, occurs in most sandy habitats, extremely common
Globe Sedge (Cyperus croceus (Cyperus globulosus))
Almost identical to Cylindric Sedge. Differs in that the seed heads are globular instead of cylindrical.
Season: perennial
Stem: densely tufted
Height: up to 20 inches tall
Roots: fibrous, may form short rhizomes
Leaf blade: bright green, flat, smooth
Seed head: with 3–7 leaf-like bracts at top of stem, few to several branches of tight globular clustered spikelets, green and turning brown to black at maturity
Propagated by: seeds and very short rhizomes
Comments: grass-like, occurs in dry to moist sandy habitats, extremely common
Surinam Sedge (Cyperus surinamensis)
Season: perennial
Stem: erect, triangular with rounded edges, covered with downward curving prickles
Height: up to 3 feet tall
Roots: fibrous
Leaf blade: up to 1/2 inch wide, green, flat
Seed head: numerous, flattened, heads of spikelets, subtended by a few to several leaf-like bracts
Seed: triangular, 1/32 inch long, tiny bump at bottom end
Propagated by: seeds
Comments: found in ditches and moist, wet sites, easily identified by lightly pulling fingers upward on the stem to check for the downward curving prickles
Texas Sedge (Cyperus polystachyos)
Season: annual
Stem: erect, rounded, smooth
Height: up to 20 inches tall
Roots: fibrous
Leaf blade: up to 1/8 inch wide, basal
Seed head: few to many branches, many flattened spikelets, clustered at ends of branches
Seed: weakly triangular, 1/32 inch long, covered with tiny bumps, brownish-gray
Propagated by: seeds
Comments: extremely common, a facultative species growing in all dry and wet soils
Sedge-Like Weeds
Doveweed (Murdannia nudiflora)
Season: warm season annual
Stem: fleshy, creeping
Height: up to 12 inches tall
Roots: fibrous, rooting at nodes
Leaf blade: fleshy, alternate, narrow, lanced-shaped
Leaf sheath: soft hairs on upper margin
Flower: blue to purple, 1/4-1/2 inch wide, in open clusters
Propagated by: seeds
Comments: usually found in moist areas, can be very prolific, often spread by birds
Common Spiderwort, Spiderwort (Tradescantia ohiensis)
Credit: Photo provided by David Drew.
Season: perennial
Stem: smooth
Height: up to 30 inches tall
Roots: fibrous
Leaf blade: smooth, linear or lanceolate, folded lengthwise, fleshy
Leaf sheath: smooth
Flower: 3/4–1 inch wide, blue, 3 petals, in umbel-like clusters, clusters subtended by 1–3 leaf-like bracts, flowers throughout the year
Propagated by: seeds
Comments: prefers moist areas, often forms large clumps with numerous stems
Tropical Spiderwort, Tropical Dayflower (Commelina benghalensis)
Season: perennial
Stem: fleshy, rooting at nodes, some branching underground
Height: up to 10 inches tall
Roots: fibrous
Leaf blade: somewhat fleshy, oval, margins wavy
Leaf sheath: clasping stem
Flower: 1/8 inch wide, two bright blue and one pale blue petals, subtended by a boat-shaped bract that has the basal margins united; underground branches have flowers that do not open and produce fruit
Propagated by: seeds from both above and underground flowers
Comments: a rapidly expanding weed, not well known, quite common in open sandy areas
