Pasture Invaders

There are a number of weeds that have recently been turning up in local pastures possibly coming in of the roadsides or imported hay. One of the obvious ones has been Paterson’s Curse which landholders have reported a number of sightings this year. 

Not so well known weeds turning up is Sticky Bartsia (Parentucellia viscose) and its cousin Red Bartsia (Parentucellia latifolia), native from the Mediterranean region, are erect annual herbs partly parasitic on the roots and surrounding vegetation resulting in degraded pasture. Leaves are oppositely arranged, stalkless with coarsely toothed margins. The Red Bartsia is slender and hairy with red-purple flowers with narrow lips. The Sticky Bartsia is sticky and hairy with yellow flowers and broad lips. These plants mainly spread by a very fine seed carried by wind and water. These are spring to summer flowering liking moist sites in pastures. These weeds can be fairly invasive if left unattended and can be controlled with a selective herbicide. Other seasonal imports are Bathurst Burr, Saint Johns Wort, and Thornapple.

Tree Tobacco

Tree Tobacco (Solanum mauritianum). Recently a landholder asked me to identify a plant that when she came in contact it gave her a very nasty rash. On inspection it turned out to be the South American plant Tree Tobacco, a large shrub or small tree growing to 4m. Densely clothed with fine velvety hairs on branches, flower parts, stalks and under surface of leaves. It has very large leaves and small purple flowers All parts of the plant are poisoness but particularly the leaves and unripe green berries and has a smell like tar. This plant is highly poisonous to humans, cattle and pigs, and can possibly cause death if ingested.

Tree tobacco spreads by seed be carried by birds, water, possums and dumped garden waste. Has a high dumpage rate as the plant becomes shabby and loses its appeal. Easiest way to control is by cut and paint method but remember to avoid direct contact with all plant material.

Arum Lily (Zantedeschia aethiopica)

Sometimes referred to as the funeral flower this plant can choke out waterways and wetlands. This perennial herb grows to 1.5 m tall and is evergreen. It is considered highly poisonous to all animals. In humans it is said to cause eczema. Australian hospital records indicate that these plants are a common and significant cause of child poisoning. It is mainly spread by rhizome and seed carried by birds, water, contaminated soil and dumped garden waste. Widely available in nurseries, garden centres and markets. Once established this is a very difficult plant to remove, there is a gel type herbicide available using the cut and paint method.

Pampas Grass

Weed Talk: By Martin Chatfield Landcare Community Weed Officer Pampas Grass( Cortaderia selloana) Pampas grass is a widespread environmental weed common in South Gippsland having been planted as an ornamental, for fodder, windbreaks and to stabilise soil. It is highly invasive , particularly in forest areas, roadsides and wetlands. It is a very aggressive coloniser, particularly on disturbed open sites. They form dense stands that exclude most other ground flora and impede overstorey recruitment. Individual flowers heads contain up to 100,000 seeds with viability exceeding 75%. Wind may disperse seed for several kilometres. Roots grow up to a depth of 3m with a spread of 4m helping established plants to tolerate extended dry spells. The large volume of dried leaf matter on and around tussocks dramatically increases fuel loads within infested areas increasing fire risk. Interestingly until the 1970s Pampas grasses in Australia consisted of low fertility strains or female plants and did not tend to have the weedy characteristics they have today, the reason they are these days during the 1970-80s large volume of seeds were imported that included higher fertility strains and male and bi-sexual plants, with the consequence that plants are know freely reproducing and spreading by seed. To control smaller plants can be dug out, all rhizome material should be removed. Where plants can not be treated immediately spread can be limited by removing emerging flower stems, cutting them at the base usually prevents them from redeveloping. Alternatively cut off maturing seed heads and placing in bags then bury or burn off site. Plants can also be sprayed with Glysophate.

Environmental Vandals

Weed Talk: By Martin Chatfield Landcare Community Weed Officer Environmental Vandal Bluebell Creeper (Sollya heterophylla) This is another one of those West Australian native invaders over enthusiastically populating our bushland and gardens. It is an evergreen woody based twining climber with attractive blue flowers. In Victoria it is classified as an environmental weed. Plants smothers ground-flora and small shrubs, overtops low growing vegetation. It is hardy and adaptable, tolerating moderate frosts, partial shade or full sun and extended seasonal dry periods. While preferring lighter soils, plants will establish in heavier soils provided drainage is good. Birds are the main cause of spread by dispersing the fruit from near by gardens. In Victorian coastal woodlands thousand of seedlings emerge following fires or soil disturbance. This has become a popular widely used ornamental plant over the last 30 years available in nurseries, and is in danger of becoming more wide spread due to its disguise as a local native plant. To remove Bluebell Creeper it can be hand pulled to prevent regrowth ensure all roots are removed. Plants can be cut and painted with glysophate in spring or early summer letting the above canopy to die back. Where plants can not be treated immediately, seedlings can be prevented by severing vines at the base in spring and early summer before the fruit develops, as regrowth occurs undertake follow up control. Early detection is desirable and control to prevent further spread. Be aware of what you by at nurseries and markets it could be your next garden nightmare.

Cape Ivy

Weed Talk: By Martin Chatfield Landcare Community Weed Officer Cape Ivy. Delairea odorata. Origin South Africa. Cape Ivy is not called odorata for nothing; it is currently in flower and is quite fragrant. Did you know? • Cape Ivy is an invasive plant and a very serious threat to indigenous vegetation. • It is a vigorous climber which strangles or smothers indigenous vegetation and creates harbor for foxes and rabbits. . • Once established, the spread of Cape Ivy is usually vegetative and by seed. • Cape Ivy can root from any stem parts that touch the soil. • It especially likes moist areas. • Cape Ivy was introduced as a garden plant and may be available from commercial nurseries. • Likely to be toxic to both people and animals. Best methods for control Start with vines growing up trees to prevent flowering and further spread by seed. Cut climbing stems with secateurs and leave to die in shrubs or trees. Gently hand pull or dig up stem runners. Follow the long runners to their source, carefully removing these and forking out main roots. Large Established Plants. Treat as for small plants except carefully dig out roots or stems on the ground, or Immediately paint with a suitable herbicide any cut stump that is to be left in the soil. For large infestations spray foliage with herbicide, but avoid spraying any native vegetation that the plant is climbing vegetation that the plant is climbing through. If using herbicide, paint/spray when plant is actively growing. For further information on Cape Ivy control or any other weeds ring, .

Poisonous Plants

Weed Talk: By Martin Chatfield Landcare Community Weed Officer. WOSPA (weeds of significant poisonous attributes) Hemlock (conium maculatum) Classification: noxious, regionally controlled. Hemlock contains five toxic alkaloids which vary in concentration due to climatic conditions. The fruit, vegetative parts and roots are all poisonous to humans and stock. The Greek philosopher Socrates is said to have been executed with hemlock. In Victoria a child died from hemlock poisoning in 1994. Handling the plant can cause dermatitis in some people. This weed is often mistaken for carrot weed emerging in autumn with its leaves deeply divided with a ferny appearance; masses of small white flowers develop in late spring -early summer and then it dies back. Hemlock will colonise areas of bare ground in pastures and bushland and prevent the growth of more desirable species. Small infestations can be hand pulled but heavy rubber gloves should be worn. Larger areas can be foliar sprayed with the specified registered chemical. Caper Spurge (Euphorbia lathyris) Classification: environmental weed. This nasty plant has a milky-like sap is heavy in alkaloids and can cause irritation and swelling to the human body, particularly sensitive areas such as the eyes. It has also been associated with stock poisoning. The juvenile plant has a stout erect stem with leaves opposite with a bluish-green colour. A white line runs the lengths of the leaf. When the plant matures it takes on a bush form. I have often seen this plant being sold at markets. Grubbing or pulling out plant is effective once again wear rubber type gloves and avoid skin contact with the white sap. . . .

Australian Native Weeds

Weed Talk: By Martin Chatfield Landcare Community Weed Officer. Australian Native Weeds. Sweet pittosporum (Pittosporum undulatum) is one of an increasing number of native species acting as an environmental weed in habitats outside its natural ecological range. Prior to European settlement the distribution of Sweet Pittosporum was believed to encompass a range of habitats including wet and dry forests environments, riparian and coastal areas along the eastern seaboard of south-east Australia The seeds are mostly spread by birds, brush tail possums foxes and black rats. You will often see bird poo haloes around the base of other trees and as Sweet pittosporum is happy to grow in the shade they can then dominate the area causing other native species to die back (allelopathic effect) and becoming a mono culture. Control measures for this plant need to be implemented otherwise a serious decline in indigenous species will result on invaded areas. Some methods are manually pull out small seedlings, cut and paint, drill and fill, or basal bark spraying with appropriate herbicides. Cape wattle (Paraserianthes lophantha) is a West Australian native which spreads along roadways and bushland. This is a rapid growing evergreen tree producing thousands of long lived seeds with buried seeds viable for many years. It is often mistaken for local native silver and black wattles. Cut and paint method is the easiest way to control this pest. . . . Anyone who would like further information or would like me to visit your property to talk weeds and their control can ring me on 56 821934 or mobile 0428317928.

Tree Weeds

Over the last 150 years or so many exotic trees have been imported into Australia only to discover many have weed type characteristics spreading out of there original placement out into the landscape by fruit and seeds eaten by birds, foxes, also spread by wind and water. Examples are hawthorn, wild cherry, willow species, box elder, desert ash, cape wattle, pine and tree tobacco. Problems occurring:`

• They take up lots of physical space
• They can create impregnable barriers of thickets
• They have a large area of soil occupied by roots
• They sometimes send up suckers a long way from the parent plant even have the original tree has been removed. A good example here would be Elm trees
• They alter the microclimate
• They may alter the soil chemistry
• Willows clog up waterways

Weedy trees favour the growth of other weeds beneath their canopies. They provide additional perching and roosting places for birds from which weed seeds are deposited in droppings. ‘Bird poo haloes’ containing numerous bird dispersed weeds such as boxthorn, bridal creeper sweet pittosporum and blackberry.
Weed trees can be removed by cutting down as close to the base as possible and pasting glysophate herbicide on the cut stump surface. This must be done with 10 to 30 seconds of the cut being made otherwise the stump will seal it self and chemical will not penetrate. The tree should not be under stress; normally spring to early summer gives best results.