Since I started at Westgate Park 16 years ago we have always thought about taking plants to the Herbarium to get a positive ID. Finally, last week I did. There are a number of plants in the Park we are unsure about and may in fact be weeds.
Of the five species we had tested, two were weeds and three indigenous. Two weedy juncus species that arrived independently and were spreading rapidly will now be eliminated.
Interestingly, one pond weed that has just arrived and was spreading fast, turned out to be indigenous and is rare in Melbourne. It is Elatine gratioloides – Waterwort and it can stay and find its own niche.
So two weeds will be eradicated and one rare plant can spread. At $150 for five plants it is not cheap but a very productive use of our funds. I intend to use this service again when money permits. There are quite a few more plants out there with a question mark.
Ed. See our Threatened species page in the top menu for conservation of other plants.
With autumn rains (limited as they have been), the plants that retreated over summer to bulbs, corms, tubers etc are beginning to break the surface. It is always fascinating to see what emerges especially after an above average dry spell.
One of these plants is the delightful Blue Stars (or Blue Squills), Chamaescilla corymbosa. We have been successfully growing them in the nursery and building up numbers. Every season we get a stunning display of blue flowers in the tubes and pots. Three years ago we planted out in the park a substantial number in varied situations to see where they would do best.
The results have been disappointing. Some re-emerged and flowered but others did not come up at all or disappeared shortly after emerging. They may not have endured dormancy or have been picked off early by rabbits, possums or snails. To counteract rabbits we built wire fence enclosures about 1 metre high but even then there was little success. Thinking perhaps possums were climbing over the fence, we have put wire across the top as well. We now await to see how successful this has been. These enclosure are a magnet for vandals and need regular reconstruction.
However, we must ask if we want to have these plants caged behind ugly wiring. Perhaps there are some plants no matter how desirable that are just not a feasible proposition in the park. Fortunately other lilies are far more resilient. Chocolate Lilies, Vanilla Lilies, Bulbine Lily, Hypoxis and Blue Star Lily seem to withstand most of what is thrown at them.
We will persevere with Blue Stars because they are so special and may find a way to sustainably and attractively grow them in the park. For now at least there is always the welcome yearly display in the nursery for our staff and volunteers.
According to The Orchids of Victoria by Gary Backhouse and Jeffrey Jeanes published MUP 1995, the orchid family [Orchidaceae] is:
… one of the largest and most diverse plant families in the world. It contains somewhere between 20,000 and 35,000 species in over 800 genera which is almost 10 per cent of the world’s flowering plants.
Australia has about 1000 species, of which over 270 are found in Victoria. This is an orchid flora of extraordinary richness, comparable with the best in the world for its range of terrestrial orchids…
We have been reluctant to plant out the many orchids we have in pots because there are so many rabbits in the Park keen to eat them! We acquired most of our orchids from a development site north of Melbourne and have been successfully propagating them in the nursery.
Acianthus pusillus – Small Mosquito Orchid
Acianthus pusillus is one of three Acianthus orchids in Victoria. They generally grow on light sandy soils in a variety of habitats including heathlands but Acianthus pusillus occurs in closed coastal scrublands, open forests, woodlands and some closed forests in a range of soil types. Dormant in summer, they appear following late summer and autumn rains and flower in the cool months of autumn, winter and spring. The flower stem grows to around 20cm. Pollination is by small gnats attracted to the flowers by nectar rewards and floral fragrances.
There are eight named species of Corybas found in Victoria, usually in the southern and eastern near coastal regions. The grow in heathlands and other damp, sheltered areas, often under dense undergrowth. They are all very small, leaf-hugging and dormant in summer with tuberoids beneath the soil. Growth commences after autumn and winter rains, flowering in winter and spring. According to The Orchids of Victoria, pollination is believed to be carried out by small fungus gnats, the flower mimicking the fruiting body of a fungus in colour, form and perhaps odour, to attract the tiny insects.
Corybas fimbiatus – Fringed Helmet Orchid
Corybas aconitiflorus – Spurred Helmet Orchid
Corybas aconitiflorus is an uncommon species but where it does occur it is found in large numbers and in eastern coastal and hinterland areas. It flowers from May to June, sometimes up until August.
The 55 species of Diuris occur only in Timor and Australia and they are widely distributed in Victoria other than the Mallee and higher parts of the Eastern Highlands in widely varied habitats and soils. Dormant in summer, growth resumes after autumn rains from fleshy underground tuberoids.
Diuris corymbosa – Wallflower or Donkey Orchid
Diuris corymbosa grows in dense colonies and is one of the most beautiful orchid species. It is pollinated by small native bees attracted to the colour and scent and flowers from September to November, prolifically after bushfire.
Diuris lanceolata – Golden Moths, Snake Orchid
Diuris lanceolata is widespread and locally common throughout much of Victoria preferring grasslands, woodlands, open forests and alpine meadows on well drained sandy loams to heavy, waterlogged peaty soils. It mainly flowers from September to October.
Microtis parviflora – Slender Onion Orchid
The Microtis genus also grows in a wide range of habitats. The tiny flowers grow spirally along a single terete leaf and flower most prolifically after fire. Microtis parviflora is very hardy, colonising lawns and nature reserves. This orchid is planted out in our heath areas but at first glance is barely recognisable as an orchid.
Pterostylis is a large genus with 60+ species in Victoria alone.
Pterostylis nutans – Nodding Greenhood
Pterostylis nutans grows in a wide range of habitats across most of the State and can be found in a few small reserves and remnant bushland close to Melbourne. The plants die back every year and mostly propagate by seed. It’s nodding flower is a very effective pollination insect trap. The labellum (hairy, red, tongue-shaped part) is triggered when a fly or mosquito lands on the surface and snaps upwards, forcing the insect to struggle out picking up pollinia on the way. Flowers July/August.
Pterostylis concinna – Trim Greenhood
Pterostylis concinna forms huge colonies in open forests in well-drained, moist soil, in full shade to full sun. It is considered vulnerable in Victoria to continued depletion. Flowers May to September.
One of our biggest challenges is to progressively remove non-locally indigenous and invasive plant species put in over large areas of the Park two decades ago and to revegetate. We are doing this because we consider it important for biodiversity and sustainability that the Park has integrity in representing the plant communities that existed within 5km of the CBD. This way the Park will more likely attract bird and insect species once common in the area.
We were very grateful to have the help of a team of 13 staff from the ANZ to assist our Friends team in clearing a large area on the hill between the southern edge of the Main Freshwater Lake and Horseshoe Lake. Quite thick trunks are cut by handsaw and hauled to the edge of the path, ready to be chipped and returned as mulch. This is hard, physical work and we continue to be impressed by the willingness of corporate teams to ‘put in’ in the way they do.
Spring is the most spectacular time for flowering in the Park although many of our locally indigenous plants flower for most of the year. Some are tiny and inconspicuous, others showy and colourful and some don’t look like flowers at all. The acacias are finishing, the peas in full bloom and the dianellas and the grasses are just starting.