Thursday, August 20, 2009

Broom burns

Cape Broom (Genista monspessulana) English Broom (Cytisus scoparius) Flax-Leaf Broom (Genista linifolia) Broom species are currently (August) in flower and can be easily identified this time of year infesting roadsides and bushland with their distinctive yellow pea flowers. It is highly flammable so thickets along roadsides and in native vegetation are an increasing fire hazard. By Christmas they form numerous hard seeds in pods and on a hot day pop the seeds out in their thousands. The seeds can last up to eighty years in soil. They are mainly spread through grading, slashing, water, and vehicle tyres. Broom can also be poisonous to stock. In South Gippsland these broom species are all classified noxious, regionally controlled which means it can not be sold or transported and landholders are expected to control and prevent its spread on their land. Brooms are native to scrub and open woodlands in the Mediterranean region, Europe, Portugal and the Azores. It was probably introduced to Australia as a garden or hedge plant and was widely planted last century. Once in infestation has taken hold it can potentially take up to twenty years to eliminate, so early detection is important. Small plants can be hand removed if the soil is soft enough, larger plants could be slashed before flowering and spray any re growth or foliar spray the whole plant with the registered chemical. Cut and paint with herbicide is also an option

Tuesday, August 11, 2009

Fennel

Not many people would realize that fennel in Victoria is classified a restricted noxious weed meaning that it is illegal to sell or transport. It is a widespread weed of disturbed land, found along waterways, grasslands and woodlands. Dense infestations can eliminate most other ground flora and can impede regeneration of native species. Distinctive by its strong aniseed smell when young has a very ferny like appearance then it shoots up to clusters of tiny yellow flowers, then produces many seeds which are distributed by water and wind. When crowns are disturbed or dislodged and come in contact with the soil vegetative production can occur. Therefore slashing will spread it even further. To control fennel it can be dug out making sure to remove all of the taproot. Material should be disposed carefully. Plants can be treated with the cut and paint method or a selective herbicide.

Cape Ivy

Delairea odorata. Origin South Africa. Cape Ivy has the ability to smother native vegetation making it a very serious threat to many ecosystems. Locally is happy to infest roadsides, along rivers and creeks being very effective at competing for light due to their ability to cover the canopy of the plant they are growing over such as tree ferns either killing the plant or causing it to break and collapse. Did you know? • 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.

Spanish Heath

Classification: Environmental weed. There is a large invasion of Erica species which originate in the Europe and Africa, many being potential weeds in Australia. Spanish Heath has become widespread in South Gippsland appearing along roadsides and infesting native vegetation. The Erica Baccans commonly sold in nurseries is also a potential weed for the southern regions being very similar to Spanish Heath. Driving round the local roads at this time of year Spanish heath is easy to spot with its white and pink very small tubular flowers. It is an erect shrub growing up to 2.5 metres. Key Points • Spanish heath produces numerous tiny seeds with a life span up to 4years and spreads by wind, vehicles and water and is highly flammable. • If the plants are burnt or broken they readily re grow from the lignotuber or butt. • Small plants can be hand pulled. Mature plants can be cut and painted with herbicide. • Other Erica species are invading native vegetation in southern Australia and species growing in gardens may become weeds in the future if allowed to escape. • Accurate weed identification is essential—weedy Erica species are sometimes confused with native heaths. Our local native Common Heath (Epacris impressa) is often mistaken for Spanish Heath • Apply control methods for Spanish heath to other weedy Erica species.

Saint John's Wort

Saint John’s wort was introduced from Europe as a garden plant and for medicinal purposes in the 19th century; unfortunately because of its aggressive weedy characteristics it readily invades pastures, bushland and grasslands. In South Gippsland it can be seen along railway reserves and some pastures. It has become highly invasive in the east of the state. It has clusters of bright yellow 5 petal flowers, the leaves are small and dotted with oil glands and gives a perforated appearance when held up to the light. Flowers early spring through summer, becoming reddish-brown in late autumn-winter because of mature fruits and old stems. Up to 30000 seeds can be produced from each plant annually and can last for 12 years in the soil. It is spread mainly by wind, machinery slashing and contaminated fodder. Saint John’s wort contains the alkaloid hypericin, which causes photosensitisation in any mammals that ingest it, resulting in blisters on weakly pigmented parts of the skin. Small plants can be removed by hand as long as all plant and rhizomes are removed. Larger infestations can be controlled with appropriate herbicide. In South Gippsland Saint John’s wort is classified noxious, regionally controlled which means it can not be sold or transported and landholders are expected to control and prevent its spread on their land.

Gorse

Classification noxious, regionally controlled. Gorse a weed of national significance was introduced to Australia during the early 1800s as a hedge and ornamental plant. In the Foster and Welshpool area where there is a fair bit of gorse around in the past has been planted and as the gold mine tailings have been moved to different areas seed has been spread infesting further a field. The annual cost of gorse management to agriculture and forest industries across Australia was estimated at 7 million in the year 2000. Living gorse is highly flammable, retains dead vegetation in its canopy, and contains flammable oils. Dense gorse patches increase the risk of wildfire and are a particular hazard near buildings, infrastructure and along fence lines. It invades and dominates bushland, pastures, forest plantations and spreads along roadways. Gorse produces yellow pea type flowers twice a year distributing its seed in the warmer months. A mature bush can have up to 40 thousand seeds in the soil around it per square metre. Seed is viable in the soil for up to 25 years. Gorse can be cut and painted with herbicide but can be difficult because of the sharp spines. Young seedlings are soft and can be pulled out. There are registered chemicals available but to assist the chemical uptake add a penetrant. Infestations normally have to be carefully monitored and retreated on an annual basis.