September 2019


Volume 46 No 7

Weather and Gardening – when will it rain?

A MSLP (Mean Sea Level Pressure) analysis map of the Southern Ocean showing
a the pattern of weather systems circling the Antarctic and affecting Australian weather.
Image: BOM

This is the title of the talk to be given at our next meeting on Saturday 28th September. It is a topic close to the minds and hearts of many people in Eastern Australia at present. Our speaker will be Julie Evans. Julie is a retired meteorologist from the Bureau of Meteorology in Sydney. Her final role there was as Manager for Media and Community Relations for NSW. Her duties included media spokesperson during significant weather events. Previously Julie has worked in climate consulting, severe weather forecasting and was part of the weather services team for the Sydney Olympic Games.

During the talk she will introduce information about climate drivers influencing Sydney weather, and explain the weather systems that bring rain to our region. This information will help us gardeners to plan garden activities, taking the approaching weather into account, and so improve the results of our endeavours.


Calendar

Sept

Sat 28 Meeting at Gumnut Hall, Gumnut Place Cherrybrook at 2pm with guest speaker Julie Evans on ‘Weather and Gardening – When Will it Rain?’

Oct

Wed 9 Propagation at Bidjiwong Community Nursery 10am to 1 pm
Sat 26 Botanic Gardens visit – History and Heritage Tour including Orchid glasshouse

Nov

Wed 13 Propagation at Bidjiwong Community Nursery 10am to 1 pm
Sat 23 Meeting with speaker: Director and Principal Soil Scientist, Simon Leake (CPSS) on “Soils and vegetation of Barangaroo”


NSW REGION GET TOGETHER NEWCASTLE

16-18 AUGUST 2018

Every year one of the Regional Groups organises a Get Together of Australian Plants Society members. This year it was held in Newcastle. 100 members attended including five of from Parra Hills Group.

It was the first time I had attended one of these events and I am sure it won’t be the last. It was a very well organised event with a great program and lots of interesting people to meet.

On the Friday night there was a President’s dinner for NSW Region Board members and Presidents and Secretaries of local groups. I attended as Secretary of our Group and Tony Maxwell attended as our representative on the Board. There were 12 groups represented at the dinner. It was a very useful time to hear about developments for NSW Region and to hear what other groups are doing.

On Saturday the program started at the Hunter Region Botanic Gardens which are located in the Hunter River Wetlands on the Pacific Highway north of Hexham.

Our first and only speaker was Stephen Bell from the University of Newcastle who has just published a book on the endemic Flora of the Hunter Region. There are over 350 species and this book only deals with trees and shrubs. His talk was therefore about trees which are only found in this region. There seem to be three real hotspots for endemic species in the Hunter Region – the Brokenback Range at Pokolbin, Mt Dangar near Denman and the Goulburn River National Park at the top of the region near Mudgee. This was such a fascinating presentation I was quite sorry when it finished.

After a lavish morning tea we split up into groups for guided walks in the gardens. The gardens have been laid out in themed gardens. Our visit was first to the Rainforest Garden which we found so fascinating our guide chided us for being too slow! No one had warned her that Australian Plants types hold the record for being the last to ever finish a bushwalk. So we didn’t see a lot of the gardens but what we did see was very lovely.

After lunch at the Gardens we drove out to Boat Harbour at Port Stephens to be guided on a walk of coastal heathland. The location had been chosen for the wide variety of plants flowering in August. We found this to be true. As well as some lovely heathland plants we also saw three species of Petalochilus – carnea, catenatus and the rare hillmanii.

Microsorum punctatum
Caladenia hillmanii, also known as Petalochilus hillmanii

The orchid is named after Nelson Bay local George Hillman who first recognised that it was a distinct species. How anyone located this plant was amazing. It was hidden away under stunted casuarinas. The track ended on a rock shelf with steep dykes in the rock and stunning coastal views. As there was a very strong wind the waves were quite impressive.

On Sunday the glorious sunny weather continued and we headed south from the city to the Glenrock Scout Camp. This is located on Glenrock Lagoon which leads to the Pacific Ocean a short distance away. The Scout Camp was built in the 1970’s on the site of the Burwood Colliery. A railway line ran through the site to transport the coal to the port in Newcastle. It was infested with weeds such as lantana and blackberry. The ground was rock hard with coal embedded in some places. The Newcastle Apex Club became involved in the initial plantings at the site in the 1970’s and with it one of their members John Le Mesurier. He has been an active and enthusiastic volunteer at the site ever since and in 2018 was named Gardening Australia’s Gardener of the Year. He took us on a tour of part of the garden. It really is a beautiful sight. The mature gardens descend the hillside in a series of terraces to the water’s edge.

Sunday’s morning tea was even more sumptuous than the one the previous day. After so much delicious food a walk in the Awabakal Nature Reserve at Dudley was the perfect antidote. The walk started in an angophora woodland where we were shown a cluster of Pterostylis curta and then opened out into a magnificent heathland which was crowded with flowers. It is not possible to list them all but the range was astonishing – Ricinocarpos pinifolius, Eriostemon australasius, Dillwynia retorta, Correa reflexa and the most floriferous Pimelea linifolia I have ever seen. Once again the coastal views were an added bonus. There was an uninterrupted view up the coast to Port Stephens.

Pterostylis curta – Blunt Greenhood Orchid

We gathered for lunch at the Hunter Wetlands Centre at Shortlands. The story of the creation of this facility is well known. The wetlands were converted into a Rugby club and playing fields which went broke in 1981 when random breath testing was introduced. It has now been restored back to a wetlands and every time I visit there it looks even better. The wetlands now have mature vegetation and many resident and migratory water birds. It receives very little funding from any level of government but under the Rudd Government Better Schools Program an education centre was built which helps generate income. The Newcastle Group has an extensive nursery there which propagates plants for commercial contracts as well as enthusiastic gardeners such as us. We were invited in to make a choice and given boxes for our purchases on the assumption that we wouldn’t just buy one or two plants. This was correct!

A truly wonderful weekend. The Newcastle Group deserve congratulations for putting together such an interesting program which really showcased their local plants.

Report and Photos by Jennifer Farrer


Climate Change in Australia

Drought and heatwaves in 2010-2011 caused the death of 26% of mature trees in jarrah forests in south-west Western Australia.
Photo George Matusick
Dead Banksia serrata In Dural. Banksia species seem to be particularly badly affected
Photo: Pip Gibian
Marri and Jarrah trees suffering from dieback.
Photo: George Matusick
A healthy mangrove ecosystem (before the marine heatwave) at the Gulf of Carpentaria in Queensland.
Photo: Norman Duke
Mangroves along the Gulf of Carpentaria affected by an underwater heatwave. Summer 2015-2016. 1,000km of coastline was affected. Photo: Norman Duke

MEDICINAL PLANTS

Jennifer Farrer, who was guest speaker at our August meeting has kindly provided her notes for inclusion in Calgaroo this month. I have added illustrative photos. ed.

Early settlers on the whole were not willing to try Aboriginal treatments but preferred to try plants which reminded them of those they had known in Britain and other countries such as India and China.

The main health problem facing the first European settlers was scurvy as they had no supplies of fresh food and were ignorant of the food available to them in the Sydney bush. The most popular antiscorbutic was Bush Tea or Sweet Tea made from the leaves of Native Sarsparilla (Smilax glyciphylla). Soldiers and convicts trooped into the forests to gather its sweet tasting leaves, from which a bitter/sweet tea was made. It was so important that the English risked death from hostile aborigines to obtain it. The Vitamin C content is similar to tomatoes 26 milligrams per 100 grams and far less than oranges.

Another early plant used medicinally by the British immigrants was the Sydney Peppermint (Eucalyptus piperita). The odour of its crushed leaves is vaguely pepperminty and probably reminded them of their own English peppermint menthe piperita.

Smilax glyciphylla vine with ripe fruit

Its volatile oil obtained by steam distillation of the foliage was reputed to cure “cholicky” complaints and was the first plant product sent from Australia to England. As it happens the chemical composition of the two oils is very different. It was a happy accident of nature that the two oils had similar medicinal qualities and it is fortunate that Eucalyptus oil was only taken in small amounts as it is more toxic than peppermint oil.

The person credited with being the first to discover the usefulness of Eucalyptus oil was Denis Considen, Surgeon of the First Fleet. He sent a sample to Joseph Banks in 1788.

Other plants used to alleviate coughs and colds
Native mints were substituted for the related European plant. Pennyroyal. The leaves were boiled in water for 15 minutes and the tea sweetened with sugar. It was taken warm at bedtime for coughs and colds and a host of other aches and pains.

Melaleuca quinqenervia oil can be obtained by steam distillation of the leaves and used for coughs and colds and externally for neuralgia and rheumatism

Tonics
Tonic is a word that is disappearing from everyday use. A tonic is an agent which will give the body strength and vigour without any adverse side effects. The term tonic is a vague one as it refers to the treatment of certain symptoms without taking into account their underlying causes.

Melaleuca quinqenevia

Knowledge of how diseases developed and their causes was rudimentary and expert medical attention was not readily available. So there was a real need for remedies that would help to combat loss of appetite, weakness and lassitude that accompanied most illnesses.

To the early settlers tonics were very important. It is likely that after arriving here, weakened by a long and exhausting voyage, suffering from the effects of inadequate nutrition and confronted by a hostile harsh environment, they were prone to all kinds of fevers, digestive disorders and so on. Since bitters and certain other bitter tasting remedies were held in high repute as nerve tonics at that time, any local bitter tasting plants were eagerly sought and investigated for medicinal use.

In Sydney Native Sarsparilla Smilax glyciphylla was also used extensively as a tonic. It was a common article of trade among Sydney herbalists in the 19th century. A decoction was prepared by prolonged boiling of the leaves until a thin syrup was obtained. This was bottled for later use. This procedure would have destroyed the Vitamin C. It was also used as a medicine for coughs and chest complaints.

Antiseptics and Bactericides

The Aborigines knew many plants which were useful in curbing infections. The early settlers do not seem to have used many of them. It may have been the higher standard of hygiene such as the common use of soap or the widespread use of methylated spirits and carbolic acid for wound disinfection. Although early settlers did use eucalyptus oil as a reputed antiseptic which is odd as it has few antibacterial properties. Maybe its clean, crisp smell encouraged them to believe it was effective.

In the 1920’s A.R. Penfold and his team at the Technological Museum in Sydney (now the Powerhouse Museum) discovered the high germicidal activity of the essential oil obtained by the steam distillation of Melalueca alternifolia foliage.

To extract the oil the leaves and terminal branchlets of Melalueca alternifolia have to be boiled in with water and the oil separated from the condensed aqueous steam distillate . One kg of foliage will yield only between 12 and

25 gm of oil. The small oil yield and the relatively complicated procedure for its extraction may well explain why this shrub’s medicinal properties were not discovered earlier.

Tea tree oil can penetrate unbroken skin and is particularly useful in the treatment of infected fingernail beds, coral cuts, tinea, some types of boils, mouth ulcers, as well as all kinds of cuts and abrasions.

Its remarkable bactericidal properties even contributed to our Second World War effort!

An interesting application of the oil is its incorporation in machine cutting oils, the germicidal and healing properties having reduced to a minimum infection of skin injuries, especially abrasions to the hands by metal filings and turnings. Large quantities of Melalueca alternifolia oil were used for this purpose in the various ammunition annexes during World War II Sydney Technological Museum 1946.

Digestion and Elimination

The generally hot Australian climate and the lack of hygiene as well as poor nutrition contributed in varying degrees to all kinds of digestive complaints. Fortunately there are many Australian plants which can be used to alleviate some of the unpleasant symptoms of these conditions.

Astringents capable of stemming the secretion of body fluids and thus able to check diarrhoea were available from various plant exudates or extracts from the very beginning of the colony. Some of these were red or brown exudates of eucalypts and angophoras often referred to as kino. This is a word from India. Kino had been introduced to Europe in the mid 18th century from plants from Africa. The kino from Australian Angophoras, Eucalypts and Corymbia the ironbark Eucalyptus siderophloia, was collected by convicts under the name Botany Bay Kino. 200ml of Kino from the Sydney red Gum Angophora costata. Was mixed with water in a 10% solution and taken as a daily dose.

Tannins present in the bark of many trees have stringent qualities which are effective in the treatment of diarrhoea
e.g. Acacia decurrens. and casuarinas.. The kino from the scribbly gum Eucalyptus haemostoma was used to treat cuts, wounds and ulcers. It was also used as a throat gargle.

Early settlers reported using gum from wattle trees dissolved in hot milk for the treatment of diarrhoea and dysentery with good results but no one knows which wattle gum was used. The gum of the Sydney Green Wattle Acacia decurrens is not soluble in water.

Copious flow of kino from a wound near the base of the trunk of a marri (Corymbia calophylla) Photo: Hesperian

Leaves of the Native raspberries Rubus sp have been used to treat stomach upsets and diarrhoea.

Eucalyptus oil was also used to treat stomach upsets and “cholicky” complaints.

The leaves of the Native Mint Prostanthera rotundifolia have been used to ease flatulence. This is not surprising as peppermint is also used for this purpose

Manna found on the Manna Gum Eucalyptus viminalis was used as a mild laxative.

Commercial Exploitation of Medicinal Plants

Of all the Australian plants with medicinal properties only 30 have been exploited commercially and of these 20 are various species of Eucalyptus.

The pharmacist Joseph Bosisto migrated to Australia in 1848 and began the first serious investigation of the volatile oils of Australian flora. In 1854 he started the first commercial production of eucalyptus oil in Victoria. He used the process of steam distillation which is a process first developed in the Middle Ages. The leaves are placed in a vessel fitted with a lid and an outlet pipe connected to a water cooled condenser. After the addition of a certain amount of water the leaves are boiled and the steam enriched with the vapour is passed through the water cooled condenser. There the steam and the essential oil vapours are reliquefied . Since the oil and the water do not mix the lighter than water oil can be skimmed off the presents first as a red currant jelly like substance which hardens until is crystalline. There is no smell but it is astringent to taste. The active ingredient is kinnotannic acid which affects the lower intestine. Kino from Australia was introduced into Europe as early as 1810 when the gum of surface of the condensed water. This method at its simplest is still being carried out with considerable success by a number of small distillers in our country areas particularly Braidwood, Tumut, Cooma, and Casino in NSW and Bendigo in Victoria.

There are some 20 species of eucalypts used for the production of this type of oil. The species most commonly used is the blue mallee, Eucalyptus polybractea. Even though Australia is the home of the Eucalypt, only 5% of Eucalyptus oil is produced here. Portugal and Spain account for 60% of the world’s production. They derive the oil from the foliage of the Tasmanian Blue Gum Eucalypts globulus which was introduced into Europe last century as a timber tree and for paper production.

Another medicinal oil produced to this day on a commercial scale is that of medicinal tea tree (Melaleuca alternifolia). It is produced by a small number of distillers around Casino and Lismore by the same steam distillation process. Apart from its bactericidal applications , the oil is used in the flavouring industry.

Commercial production of this oil faltered in the 1970’s due to unreliable supply, inconsistent quality and lack of promotion. The foliage was hard to obtain as the species is found on swampy ground which made harvesting difficult especially in years of high rainfall. Also the oil content of the naturally occurring trees was quite variable

The situation changed in the 1990’s. Manual harvesting of variable natural stands of Melaleuca alternifolia was eliminated. Highly successful efforts to improve the seed enabled huge plantations which could be harvested mechanically to be established along the eastern coast of northern NSW, southern Qld and even inland. Australian tea tree oil is now a well established article of world trade. It is even included in the International Standards. ISO 4730.

The leaves of corkwood (Duboisia myoporoides), a native tree of the rainforests of northern NSW and southern QLD contain a large proportion of an alkaloid (hyosine) which is used in the treatment of stomach ulcers and sea sickness. The production of corkwood foliage on the north coast of NSW has been a steady if not large industry. The collected leaves are dried out of the sunlight and sold overseas to pharmaceutical firms engaged in the extraction of its alkaloidal constituents. Boehringer Ingelheim has an Australian plantation of 1400 hectatres in Northern NSW which employs 20 people in the harvesting of Duboisia myoporoides leaves for the production of the drug Buscopan.

Duboisia myoporoides – Native corkwood. Leaves
Bark of Corkwood Tree – Photo: Peter Woodward

The pale yellow resinous exudates from the cut trunks of the white and black cypress pines (Callitris sp) is sold overseas under the name of Australian sandarac. This resin is used to coat pills which are to dissolve in the intestine and not in the stomach.

The collection of the resin is a real cottage industry. Parts of the forest which have been logged more than a year previously are visited to collect the resin which has now collected on the stumps i n worthwhile quantities.

The future of the medicinal plant industry in Australia is bright as the world looks to become less dependent on the petroleum industry to produce synthetic organic chemicals. There are quite a few potentially useful plants awaiting commercial exploitation.


Parramatta and Hills District Group

SECRETARY: Caroline Franks

Email: apsparrahills@gmail.com