Yellow-flowering herbaceous plants; Senecios The Good and the Bad

Senecio species are possibly the largest genus of flowering plants with roughly 1500 species, of which approximately 50 are native to Australia (Richardson et al 2007).  A well known specie of Senecio in South Gippsland is Ragwort (Senecio jacobaea). Senecios are distinguished by having yellow flowers and alternately rranged leaves that often have stem-clasping ear-shaped lobes at their bases. Known to colonise disturbed areas and germinate quickly following bush-fires, Senecios are pioneering plants. In the scheme of a plant community, Senecios are understory plants with some species becoming invasive under ideal conditions. 

With so many types of Senecio, correct identification can be difficult. Provided you have a sample of parts of the plant; leaves, flowers etc. below can be used as a guide to at least identify the 'bad' from the 'good'.

The Bad guys

Number of introduced species of Senecio in Victoria? There are roughly 5 exotic/introduced species of Senecio in Victoria.

What are some of the ones that are found/could be found in South Gippsland?

Ragwort (Senecio jacobaea) is a major pasture weed in South Gippsland. Cattle selectively avoid grazing it so it proliferates. Poisonous to grazing mammals, both fresh and when dried in hay or chaff, ragwort causes liver damage, leading to photosensitisation, jaundice, wasting and sometimes death. 

Fireweed (Senecio madagascariensis). There are *no recorded infestations of Fireweed in the South Gippsland region, (*at the time of publication) however the growing conditions are suitable for a potential outbreak. Fireweed, like ragwort, is toxic to stock and has the potential to out compete desirable pasture grasses.  This plant is a Victorian Weed Alert Weed see Department of Primary Industries Weed Alert Fact Sheet; Fireweed (Senecio madagascariensis)

African daisy (Senecio pterophorus). Found in the Port Phillip region, African daisy as with ragwort and fireweed can cause heavy losses in agricultural productivity (being toxic to stock, avoided by cattle and costly to control).  African daisy grows in a variety of situations from well-drained hillsides to semi-waterlogged gullies making it a threat to near by West Gippsland. For identification and control see the Landcare Note; African daisy (Senecio pterophorus)

 

The Good guys

Number of Senecio species native to Victoria? 50, (too many to mention!) 16 of these species can be found in the Melbourne area alone (Gray et al 2006).

What are some of the common natives found/could be found in South Gippsland?

Firewheel groundsel (Senecio linearifolius) can be found in wet and damp forests in higher hills and gullies.  The plant has sharply-toothed, long leaves that are dark green in colour growing to 150mm long (the leaves of ragwort are 35cm long). Flowerheads are small with 5 petals (ragwort has 12-15 petals).

Rough Fireweed (Senecio hispidulus var. hispidulus) can be found in grasslands, dry and valley forests, coastal banksia woodland and tea tree heath. The plant has toothed to –lobed, long to egg shaped leaves growing to 60mm. Image of Rough Fireweed 

Cotton fireweed (Senecio quadridentatus) is the most common and widespread Senecio species, found in riparian scrub, dry and valley forests and tea-tree heath.  The plant has narrow, pointed leaves to 100mm long, becoming smaller up the stem.  

 

If the above doesn't get you to a clear point of identification, (this is likely-considering there are so many species!) then there's some great reference material to help you discover exactly which Senecio you're dealing with. See below for details.

 

References  

Introduced Senecio information;

Richardson F.J., Richardson R.G. and Shepherd R.C.H. (2007). Weeds of the South-East an Identification Guide for Australia. R.G and F.J, Victoria

 

Native Senecio information;

Australian Plant Society Maroondah (2001). Flora of Melbourne. 3^RD Edition.  Hyland House, Melbourne

 

Kate

Holly (Ilex aquifolium); a Naughty not Nice bush invader

With its glossy dark green leaves and scarlet red berries its no wonder European culture has long associated holly with Christmas time. Native to Europe, holly was introduced to Australia for ornamental use (Muyt 2001) and has now become a familiar foe in areas with cool, moist climates- including southern Victoria and Tasmania among other places.

 

Holly prefers fertile, deep, friable, moist and well drained soils- like those found within the Strzelecki Ranges. Plants are typically dormant in cooler areas over winter however they may continue to grow during mild winters and in warmer locations. Small white flowers are produced in late spring to early summer with red fruit developing over autumn- winter on female plants. On any given plant, some leaves have sharp triangular spines along the leaf edge while others are spineless.

 

The plant is of primary concern due to its impact on recreation and native vegetation. Holly forms dense thickets, (if left uncontrolled) restricting access to people and vehicles in remote areas or along poorly maintained tracks. The berries and leaves of holly are toxic to people, especially children. Reported symptoms include nausea, vomiting, diarrhoea, collapsing and unconsciousness (the fruit is not considered fatal) (Sheperd 2004). In a damp or wet forest environment, those areas once occupied by tall native shrubs will become dominated by holly creating a poor shrub layer. In turn impacting upon the lower layers of vegetation i.e. herbs and ground cover plants and preventing natural regeneration. Another feature which puts this plant on the naughty not nice list is that it provides a food source and shelter for pest animals. The berries are to some extent eaten by foxes (Garcia, Martines & Obeso 2007) as well as browsed by goats and deer (Obeso 1997).

 

To control holly seedlings and plants less than 1 metre tall can be dug out. Tops are prone to break away when pulled so if roots remain they should be dug out. All removed material should be disposed of appropriately, Larger plants can be controlled using the cut and paint or drill and fill methods. If using herbicide, treat the plant in spring- early summer when the plants are actively growing. Priority for initial treatment should be given to fruit-bearing female plants. For further information on the identification or control of holly please contact Kate Williams, South Gippsland Landcare Network Project Officer on (03) 5662 5759 or email katew@wgcma.vic.gov.au.

 

Kate

Become aware of Coastal weeds over Christmas/New Year

What do Bluebell Creeper, Dolichos Pea and Polygala all have in common? They are low maintenance plants for the garden? This is true however beyond the garden these plants are considered a threat to coastal spots including areas frequently visited over the Christmas/New Year break.

The threat posed by bluebell creeper and dolichos pea is caused by there tendency to spread and form dense matts that smother native groundcover plants and shrubs. Whilst polygala doesn't smother vegetation, (as the others do) it does dominate the understory of coastal woodland. Left uncontrolled, these processes of smothering and dominating can, among other things, simplify vegetation communities making them less equipped to support a range of native fauna i.e. less flora diversity= less fauna diversity.

On the way to or from your local beach spot over summer take the time to see if you can spot either of these plants, (or all three if you're really lucky!) Common areas to look include; next to walking paths through bush on or near sand, the edges of bush in coastal areas or roadsides. What to look for; bluebell creeper as the name suggests, is a shrubby evergreen climber with blue flowers from September to February. Come late summer to autumn the plant would have developed oval fleshy berries. Dolichos pea is a perennial vine with pale mauve to purple pea like flowers from September to January. The type of polygala species commonly found in coastal areas is Polygala myrtifolia, an erect to spreading shrub growing to 3m high. Like the flowers of dolichos pea, the flowers of polygala resemble a pea and are purple to mauve also flowering from spring to summer.

In terms of control, permission should be sought from the land manager before any weed control is undertaken. Should you identify any of these plants over summer, I encourage you to be proactive by working with other locals/visitors or as individuals to seek permission and bring about control to reduce further spread. In a garden situation, there are numerous plants that look similar and can be planted as a great alternative. The south east Victorian coastline is truly special, (hence the vast number of holiday makers come Christmas!) and therefore well worth protecting from weed invasion.

For

further information on identification and control of bluebell creeper, dolichos pea or polygala please visit www.southgippslandweeds.com.au or contact Kate Williams, South Gippsland Landcare Project Officer on (03) 5613 5973 or email katew@wgcma.vic.gov.au. Please note; the plants described above are environmental weeds and not listed as noxious under the Catchment and Land Protection Act 1994.

Broom species

Driving the roads of Victoria during this time of the year, be it at high speeds or a slow Sunday drive, it's hard to ignore the patches of yellow on roadside margins. It's a tell tale sign that spring is here when the daisy shaped flowers of cape weed and pea shaped flowers of broom species are in full bloom.

Whilst cape weed and broom are both in action at the moment, its broom that I will touch on for the purposes of this article not cape weed. The main reason being is that the optimum time to control species of broom is now and in the coming months prior to seed set in late spring to early summer.

Broom is an evergreen plant that can dominate native shrub vegetation growing 3 meters high and wide. There are three species of broom found in the region, Cape Broom (Genista monspessulana), English Broom (Cytisus scoparius) and Flax-Leaf Broom (Genista linifolia). All of the three species of broom are listed as noxious and regionally controlled within West Gippsland.

A common scenario for broom invasion occurs with the plant starting out in disturbed areas i.e. the edge of bushland or next to a water course. Over time, (if left uncontrolled) the infestation will expand into less disturbed areas i.e. within the bushland itself. It's for this very nature of invasion that broom constitutes a fire hazard. For example in roadside areas adjacent to bushland, (where fires are most likely to start) broom can form a flammable understory at the edge of a forest and spread into bushland.

Aside from being a fire hazard, species of broom are a concern to native vegetation given their ability to dominate native vegetation and severely impact regeneration of overstory plants including eucalypts and wattles for example. In addition, the seeds are highly poisonous potentially causing injury to fauna. In terms of its impact on agriculture, broom species are considered a low risk. The plant would not develop in cultivated situations and can easily be controlled by mechanical means.

For the above mentioned reasons, the opportunity to control the plants should be seised this spring. The community are working to keep weeds such as broom under control-your assistance in controlling broom on land under your control will help this effort. Small plants can be hand pulled if the soil is soft enough, larger plants can be slashed prior to flowering and any regrowth should be foliar-sprayed with the appropriate registered chemical.