Whitehorse City Council

Weed Herbs, Grasses and Bulbs

The following plants are considered to be environmental weeds of Whitehorse. They are species that invade and thrive in our native bushland where they do not naturally occur. These weeds tend to dominate, threatening the natural balance of the remnant indigenous flora and fauna of Whitehorse.

Agapanthus
Agapanthus praecox subsp. Orientalis
This perennial herb form dense clumps with long, thick, white rhizomes. It has leathery, arching leaves with watery sap that grow from the base in clumps of up to 20. Umbrella-shaped clusters of many small, purplish-blue or white flowers followed by thin, papery, black seeds.
Grows up to 1m high
Flowers: Spring and summer
Seed set: Summer. Spreads mostly by division of the bulb.

agapanthus

Angled Onion
Allium triquetrum
This perennial herb has stems which are concavely triangular in cross-section. The stems produce a cluster of white flowers each with a strong green line. The leaves have a distinct onion smell when crushed.
Grows up to 30cm high
Flowers: Late winter and spring
Seed set: Spring and summer. Spreads by bulb division.

angled onion 2
 
Black Nightshade
Solanum nigrum
This bushy annual herb has green to purple stems. It has clusters of small white star-shaped flowers often tinged with purple. Its berries are dull green when young, turning purplish-black.
Grows up to 60cm
Flowers: Spring to summer
Seed set: Ripening in late spring and summer

black nightshade 2black nightshade 4


Cats-ear, Flatweed
Hypochoeris radicata
The leaves form a low-lying rosette around a central taproot. Forked stems carry bright yellow flower heads. Once matured these form seeds attached to fine white hairs. When windborne the hairs act like parachutes to disperse the seeds.
Grows up to 60cm high
Flowers: Almost anytime
Seed set: Almost anytime

catsears 2 - Copy

Capeweed
Arctotheca clanedula
This annual plant grows in rosettes and sends out stolons enabling it to spread across the ground quickly. Hairy stems bear daisy-like flowers with small yellow petals that sometimes have a green or purple tint surrounded by white or yellow ray petals.
Grows up to 50cm high
Flowers: Winter and spring
Seed set: Late spring

cape weed

Creeping Buttercup
Ranunculus repens
This creeping perennial grows in damp degraded places. Leaves are in clusters on long stems and are almost round. Shiny yellow flowers are five-petalled, and held above the leaves on long stalks.
Flowers: Spring/summer
Seed set: Spring, summer and autumn. Spreads by creeping stems.

Creeping Buttercup

Cocksfoot
Dactylis glomerata
This grass grows in dense perennial tussocks. It has a distinctive tufted triangular flower head which may be either green or red to purple tinged turning pale grey-brown at seed maturity.
Grows up to 1.5m high.
Flowers: Spring/summer
Seed set: Summer/autums
cocksfoot 2


Couch Grass
Cynodon dactylon
The grass creeps along the ground and roots wherever a node touches the ground, forming a dense mat. It reproduces through seeds, runners, and rhizomes.
Flowers: Summer
Seed set: Summer and autumn. Plant mainly spreads by vigorous runners that take root easily.
couch


Drain Flat Sedge, Umbrella Sedge
Cyperus eragrostis
This perennial sedge often forms dense clumps. It has long, solid triangular stems with slender leaves that grow from the base of the stem.
Grows up to 90 cm
Flowers: Spring and summer
Seed set: Spring and summer

Drain Flat Sedge, Umbrella Sedgedrain sedge.2

Fennel
Foeniculum vulgare
This herbaceous plant forms large clumps. It produces numerous short-lived upright stems from a long-lived crown. Its leaves are finely divided into many thread-like segments and have a ferny appearance. Tiny yellow flowers appear in large flat clusters at the tips of the branches. Leaves give off a strong aniseed-like smell when handled or crushed.
Grows up to 2m high
Flowers: Summer to autumn
Seed set: Late summer or autumn. Plant spreads by division.

fennel 1Fennel

Kikuya
Pennisetum clandestinum
Perennial creeping grass that can form a mat. It has very long stolons that root frequently.
Grows up to 2m when supported by other plants.
Flowers: Rarely flowers locally
Seed set: Not significant. Spreads by fragments taking root and by vigorous creeping stems.

Kikuyu (2)kikuyu.2kikuyu

Larger Quaking Grass
Briza maxima
This is a short-lived slender grass. It has few leaf blades and stands upright.
The leaves are have a noticeable twist. The seed head/fruit have been described as resembling blowflies on a very fine stem.
Grows up to 60cm tall
Flowers: Late winter to early spring
Seed set: Spring and summer

Large Quaking Grass

Lesser Quaking Grass, Shivery Grass
Briza minor
This is a slender, erect and hairless grass. It has few leaf blades and stands straight up.
Grows up to 60cm high
Flowers: Spring
Seed set: Late spring and summer
Lesser Quaking Grass


Montbretia
Cososmia x crocosmiiflora
Perennial herb
This perennial forms dense clumps with underground rhizomes. Its light brown corms have a fibrous cover and form clusters of three or more at the stem base. Leaves are sword-shaped and rise from the base. Its has orange to crimson flowers.
Grows up to 1m high
Flowers: Spring and summer
Seed set: Summer and early autumn, also spreads by corns in soil.
Montbretia

Oxalis, Sourcob
Oxalis pes-caprae
This herbaceous plant grows up each year from underground bulbs. It produces a rosette of leaves at ground level. Its leaves are on stalks and have three heart-shaped leaflets. It has bright yellow flowers. These flowers open only during sunny periods and close again at night or during dull conditions.
Grows up to 40cm
Flowers: Late winter to summer
Seed set: Seed is rarely fertile but plants multiple rapidly from numerous underground bulbis.
oxalis 2oxalis 6

 

Patersons Curse
Echium plantagineum
Erect annual herb with purple flowers
Grows up to 1.5m tall
Flowers: Winter to summer
Seed set: Autumn and winter
Patersons Curse


Panic Veldt Grass
Ehrharta erecta
This is a tufted grass. It will grow almost anywhere even in shady positions. It especially likes moist conditions.
Grows up to 90cm high.
Flowers: Spring summer
Seed set: Spring, summer and autumn

Panic Veldt Grass

Spear Thistle
Cirsium vulgare
This herb is a spiny, large headed, purple flowered annual to biennial thistle.
Grows up to 1.5 m high
Flowers: Mainly in summer and autumn.
Seed set: Mainly in summer and autumn
Spear Thistle


Sweet Vernal Grass
Anthoxanthum odoratum
This perennial grass forms tufts and has elongated leaves. It has narrow and spike-like seed heads at the tips of upright stems.
Grows up to 60cm tall
Flowers: Spring
Seed set: Spring and summer
sweet vernal grass 1sweet vernal grass 2


Watsonia
Watsonia meriana var bulbillifera
This perennial forms dense clumps from stout, fibrous coated corms that multiply at ground level. The stems grow stiffly upright. Its leaves are light green arising from base. They are sword-shaped, folded, tough and fibrous.
Grows up to 2m high
Flowers: Spring
Seed set: Late spring and summer. Spreads by buds or corns on stems and main bulb.
Watsonia 1


Wild Oat
Avena fatua
This grass forms dense tufts. It has a a typical oat appearance with hollow, erect stems. It is sparsely hairy.
Grows up to 1.5m high
Flowers: Late winter and spring
Seed set: Spring to early summer
wild oats 2jpgwild oats


Yorkshire Fog Grass
Holcus lanatus
This grass forms dense tufts. Its leaves are soft and hairy which extend from a round stem.
Grows up to 1m high
Flowers: Spring and summer
Seed set: Summer and autumn

Yorkshire Fog Grass