NEW ZEALAND MIRROR BUSH

(Coprosma repens)

(Photos: E. Cousins & C. Schultz; growth habit, close-up of glossy leaves, female flower, male flower; Cape Jervis)

There are many lovely Coprosma cultivars sold at garden centres, and they make very attractive garden plants. The one pictured here though, Coprosma repens, with its big, oval, glossy green leaves, is prohibited from sale.  It is not one of the major “declared weeds” but it has naturalized in coastal areas of southern and south eastern Australia. There are several 2 metre tall specimens of this spreading shrub on the coastal reserve at Cape Jervis. Infestations often start under trees, from birds dropping seeds. There are distinct male/female forms of the small flowers, normally occurring on separate plants. In December, have a gander: work out if the flowers you see are lads or lasses!

(Hint: the female flowers have a ‘style’ with 2 thick branches; see photo above.)

EVENING PRIMROSE

(Oenothera stricta ssp. stricta)

(Photos: C. Schultz, Cape Jervis; opening and withered flowers; flowering plant; base leaves)

The evening primrose produces erect flowering spikes most of the year; the 10cm yellow flowers are tubular, with 4 petals and 8 stamens. As the name suggests, flowers open in the evening. They then redden and wither away the next day as the flower above them on the spike opens. Most of the leaves are at the base, but smaller ones spiral up the flower spike. Both sets of leaves have a pointed tip and wavy edges; however the base leaves are hairless while the leaves on the flower spikes have tiny hairs. The stems themselves are hairy too, and often woody but unbranched. Originally from South America but now naturalized in S.A., the evening primrose is classified as an environmental weed; that is, it invades native ecosystems and adversely affects the survival of indigenous flora and fauna.

TWO-HORNED SEA ROCKET

(Cakile maritima)

(Photos: E. Cousins, Cape Jervis)

This member of the mustard family is a sprawling, succulent annual, up to half a metre tall. It grows in clumps in the sand along seashores, such as Morgans Beach. Leaves are fleshy, shiny, green and deeply lobed. The 4-petalled pale purple flowers appear year round. They open from the bottom of the stalk, with fruits sometimes appearing at the bottom of that stalk simultaneously. The ‘rocket’ in the common name doesn’t come from the plant being edible like salad greens, but from the shape of its corky brown fruits … they are swollen, both with or without horns, near the base, making a ‘rocket’ shape!

AFRICAN DAISY

(Arctotis stoechadifolia)

(Photos: partially opened flower, mat formed by plant; E. Cousins, Cape Jervis)

The silvery foliage and daisy-like flower would make this an attractive ornamental in a garden … if it would just stay there! Another garden escapee, this weed is found on the coastal reserve at Cape Jervis, but it certainly isn’t restricted to there. It is a major problem in other S.A. reserves, such as the Hallett Cove and Scott Creek Conservation Parks. You’ll recognize it by its woolly stems, heavily lobed leaves, and daisy-like flowers which vary in colour from white through pink and purple. In sand dunes, it can grow into dense mats (see photo). These mats cause local plants to be lost through shading, smothering and competition for resources. Apparently, this weed can also cause the structure of sand dunes to alter, e.g. by becoming steeper in slope.

BROAD-LEAF COTTON BUSH

(Gomphocarpus cancellatus)

(Photos: plant, monarch butterfly and caterpillar; flower bud; E. Cousins; Cape Jervis)

This woody weed from South Africa grows to about 1 metre high, and competes with natives for space, nutrients and water. It has escaped cultivation as an ornamental, and has invaded many reserves and national parks. The plant seed is spread by wind and water; its sap can be an irritating or toxic to some people, so use gloves when dealing with infestations. Hand pull small plants; use cut-and-swab or drill-and-fill techniques to poison large ones. If infestations are kept under control, the cotton bush does bring one benefit. Over the winter, you’ll notice the plant has many white-purple flowers…and often plenty of caterpillars, devouring the soft leaves and stems. These are the larvae of the Monarch butterfly, which have been plentiful around Cape Jervis this year. The Monarch is not truly an Australian native (though a resident for hundreds of years!), but apparently the larvae of the Lesser Monarch, which IS an Australian native butterfly, also uses this bush as a food source!

STINKWORT

(Dittrichia graveolens)

(Photos: C.Schultz; Cape Jervis)

This annual is native to the Mediterranean region, but adapts to other temperate climes with a winter rainfall of 300-800mm. It likes open (unshaded), disturbed sites where there is sparse groundcover: roadsides, paddocks, wasteland and riverbanks; it also spreads into dry grasslands. If undetected or ignored, it can take over. The plant is aromatic, with an odour like camphor (hence the common name). In summer it grows rapidly from a rosette to an erect plant up to 50cm, with sticky, slightly hairy grey-green foliage. Hundreds of small yellow flowers appear from January to April, and fruits from February. These fruits produce massive numbers of seeds (about 15,000 per plant!), which are viable for 3 years. The 2mm seeds are hairy, with about 30 bristles each. These hairs allow them to cling to clothing, machinery, animal fur, etc., and hence enable seed dispersal by means other than wind and water. The plant can cause dermatitis, itchiness and blistering of your skin, so avoid touching it. Grazing animals are even worse off … ingested seeds can give them enteritis and kidney disease!

ATHEL PINE

(Tamarix aphylla)

              (Photos: C.Schultz; tree; close-up showing flower)

This tree was widely planted for its shade in the 1970s, but has now been listed as a “Weed of National Significance”. It is a threat to the pastoral industry, because of its invasiveness (it has already spread along 600 kms of the Finke River of NT), and its ability to dry up waterholes and rivers. It also out-competes native plants which provide food and shelter for birds, reptiles and other animals. The trees can grow to 15m tall. Though not a true pine, the tree does produce dull green leaves similar to pine needles. Light grey trunks of younger trees darken to black as the tree matures. Sprays of pinky-white flowers are followed by bell-shaped fruits containing lots of seeds. These seeds have a built-in parachute … fine hairs, to help the wind spread them. Buried broken branches can also grow into new trees.

SEA SPURGE

(Euphorbia paralias)

(Photos: C.Schultz; close-up with flower; in situ, Cape Jervis)

This is a stiff, pale green shrub, growing up to about 60cm tall around Cape Jervis.  Originally from areas around the Mediterranean, you’ll find it along the sea shore or on sand dunes here. A plant can produce up to 5000 salt-tolerant seeds, which spread on ocean currents from beach to beach. The plants then compete with (and displace) native plant species, and change the actual structure of the beach. Consequently sea spurge is a transformer weed. The transformations it causes also have repercussions for birds such as the Hooded Plover, which like open beaches for nesting.

Leaves vary in length from 5 to 20mm. The older leaves around the lower part of the stem hang down untidily as they brown off. Further up the stem, the leaves change shape, getting broader, but they are still tightly packed.  The stems themselves are fleshy, and quite thick (often over 2 cm). These stems die off annually to reshoot from a woody crown. Broken stems can release a toxic sap; be careful you don’t get this on your skin or in your eyes. The yellowy-green flowers are tiny, as you can see from the photo above (compare to the fingertip in the background).

HOREHOUND

(Marrubium vulgare)

(Photos: http://rurification.blogspot.com.au/2011/01/horehound-candy.html , http://www.herbosophy.com.au/horehound-marrubium-vulgare/, http://kaweahoaks.com/html/horehound.html  )

This plant is originally from temperate climate areas such as Eurasia and Europe. It is now a weed of pastures, and apparently affects the flavour of meat from grazing animals forced to feed on it, since it contains a bitter alkaloid. Maybe this same alkaloid is the reason it was used in some beers and cordials? The plant also invades areas of disturbed native vegetation. Horehound grows to about 60+ cm high, with stems that are four-sided.  Grey-green on top, whiter underneath, the oval-shaped leaves of horehound sit opposite each other on these stems; they look woolly, and really crinkly, with lots of deep veins. The edges of the leaves are quite scalloped. The flower heads form dense groups around the stems, near where the leaves come off.  If you have ever worn cloth garden gloves when removing these flower heads, you’d know how clingy the fruit or burrs are…not a good idea! No wonder they get carried easily by animals in their fur.

ONION WEED

(Asphodelus fistulosus)

(Photos: http://vro.dpi.vic.gov.au/dpi/vro/vroimages.nsf/Images/weeds_onion_weed_plant/$File/onion_weed_sa.jpg, http://ca.wikipedia.org/wiki/Porrassina )         

The numbers of this weed have been increasing over spring-early summer on the verges of Flinders Drive, towards the ferry terminal. Several of our volunteers have removed heaps near the bench seat and traffic sign. The plant grows to shin high, and is easily identified: the leaves have the same round, hollow, fleshy look of normal onions. However, it doesn’t produce a bulb like a ‘normal’ onion, because it isn’t really an onion. The flower stems produce star-shaped flowers (white with a stripe of reddish-brown), along the length of the stem. These are followed by berry-shaped fruit containing numerous seeds, thought to be viable for years. The plant can proliferate in disturbed agricultural land as well as on the road verges, and have a preference for drier regions. For small outbreaks, remove flowering stalks and seed heads, and dispose of carefully. The remainder of the plant can be dug up with its roots, and turned upside down to dry out and die. Large outbreaks are much harder to deal with, so be vigilant!