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Into Horticulture

Issue 6   February 2012

Plant & Garden News

Fraser Coast's Chinese garden well underway
Construction of the Chinese Gardens in the Hervey Bay Botanic Gardens is moving forward with a consignment of bricks, tiles and ornaments arriving from China. Garden designers and landscapers from Hervey Bay's sister city of Leshan have helped plan the garden, which will include a moon gate, water features, bridge and pavilion, but work will be completed be Council staff and local contractors. An Australian garden will be created in Leshan. Source: Building materials arrive for Chinese Garden

Bee threat arrives in Townsville
Asian honeybees have been detected at the Port of Townsville on a cargo vessel. Vegetation and potential nesting sites in the area will be inspected to ensure that the bees have not spread, with the help of an odour detection dog. Source: Hunt is on for Asian honeybees in Townsville

New hope for rare Westringia
The Snowy River Westringia (Westringia cremnophila), last seen in the wild in 2002, has been found again. They only occur on sheer cliffs along a short stretch of the Snowy River requiring white-water rafts to access. The relatively high number of plants found on this expedition (only four were seen in 2002) was a good sign for the survival of the species, but cuttings were also taken for propagation at the Royal Botanic Gardens Melbourne. Source: Living on the Edge! - Rare plant continues to hang on

Legumes invite rhizobial bacteria in
Some more light has been shed on the special relationship between nitrogen-fixing bacteria and their legume hosts through recent UK research. After recognising a signal from the bacterium, the plant actually allows controlled access by supplying enzymes that break down the plant cell walls, guiding it to the correct cells for nodule formation. Source: Legumes give nitrogen-supplying bacteria special access pass

Night-flowering orchid discovered
The first known night-flowering orchid has been discovered on an island near Papua New Guinea. Even though many other orchids are pollinated by moths, their flowers remain open during the day. In contrast, the flowers of Bulbophyllum nocturnum open after dark and close in the morning. They last only one night. It's pollinator is as yet unknown, but could be a midge. Source: World's first night-flowering orchid is discovered

Space research provides hints for earth
Scientists developing methods for growing food in space have found that sweet potatoes can be trained in a compact vertical arrangement without sacrificing yield, provided the main shoot is retained. Side shoots can be trimmed away, while the main vine is wound around cylindrical or conical cages. The researchers say that hormones produced at the shoot tip stimulate root development. They also say that sweet potatoes are a relatively unfussy crop, making them ideal candidates for the "generalized-growth environment" likely in future space agriculture. Source: Thanksgiving in space may one day come with all the trimmings

Cannonvale Botanic Gardens ready to plant
Planting will start soon at Cannonvale Botanic Gardens. Two themed areas, the "Beach Rainforest Garden" and the "Dune and Swale Garden" will be part of stage one, with stage two anticipated to begin mid 2012. Whitsunday Regional Council hope that the gardens will eventually become a tourist attraction for the Cannonvale and Airlie Beach area. Media release: Planting to start in Botanic Gardens (PDF)

New fire ant incursion thwarted
A nest of fire ants in crated mining equipment imported into Queensland from the USA has hopefully been prevented from turning into a new fire ant outbreak. It was quickly dealt with and will be followed up with bait treatments and an investigation. The equipment was due to be shipped to Perth. Source: Quick notification saves potential fire ant threat to Roma

Salvinia inspires engineers
In another example of plant design inspiring industrial progress, the aquatic weed Salvinia has helped engineers develop a new plastic coating. The leaf is covered with specialised hairs which help it cling to the water's surface (aiding stability) while at the same time trapping air to assist buoyancy. Mimicking this arrangement has led to a coating that could be developed for use on watercraft with similar effect. More from Ohio State University: Plant with "eggbeater" texture inspires waterproof coating

Madeira vine biocontrol program underway
A beetle from South America has been released in various locations in SEQld as a biocontrol against Madeira vine (Anredera cordifolia). Biosecurity Queensland says that it's been tested on 37 related plant species without damage. Results from the first release are promising, and more releases are planned in infested areas over the next two years. Source: Small beetle to control a big problem

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It's been a funny old summer in SE Queensland. Unusually cool with lots of rain and overcast conditions generally, it's been rather gloomy. Meanwhile, out in the wider world, it's pretty gloomy too, with 2012 getting more and more "interesting".

Don't forget what great value plants can be, whether it's enhancing your own personal environment or as a gift. Even common plants can look great with a little care and appropriate pruning, so don't dismiss neighborhood survivors (with the exception of weeds, of course) that can be obtained cheaply or propagated from for free.

Nevertheless, more experienced gardeners will inevitably want to start collecting some of the more unusual plants seen in books and magazines, but it seems to be getting increasingly difficult to find plants even slightly outside the mainstream these days.

If you know of an little nursery somewhere in Australia selling unusual plants that deserves more customers, please get in touch, especially if they do mail order. (subscribers can reply to their email, otherwise use the contact info at

Until next time, Happy Gardening!

Valentines Day Gift Ideas

The next big day in the merchandiser's calender is Valentine's Day (14th February 2012). Instead of cut flowers, how about a more enduring token of your affection? Some ideas:
» An indoor plant for their desk, in an appropriately-themed decorative pot
» A feature tree planted in honour of your love. Finish with a red ribbon. Watch it grow and blossom together.
» Plant bearing the same name as the object of your affections (e.g. Tibouchina 'Noelene'), or with terms like "love" or "sweetheart" in the name. See Plants with special names for some suggestions.
The gardens in early 2008 (top) and in late 2010 (bottom)
Feature Article

The Kilkivan Community Gardens & Railway Markets Project

The township of Kilkivan, west of Gympie, is at the end of the first branch line to be constructed in Queensland. Sadly, the Theebine to Kingaroy rail service ceased in 2007, but fortunately the Kilkivan Community Gardens & Railway Markets Project is creating beauty and a new life for the former station.

Established in 2001 by a group of like-minded residents, one of the Project's early undertakings was the establishment of a garden featuring native plants. The gardens have since become a wonderful asset to the town.

Another achievement is preservation of the station's goods shed.

Work is ongoing and is all done by volunteers with some assistance from "work for the dole" participants. To assist with funding, Sunday morning markets were started in the grounds in 2004. There's also a garden expo each spring and other events staged throughout the year.

To learn more, including information and directions to the markets and other attractions in Kilkivan, visit

Acknowledgment: Thank-you to members of the Kilkivan Community Gardens & Railway Markets Project, Inc., who supplied information and images.

Queensland Garden Events 2012

The diary at, which covers all of Qld, is beginning to fill out - please keep those dates coming. If you're taking a trip later in the year you might like to see what's on and plan your itinerary to take in a show or garden opening.

The Science of Horticulture

Stomata - an overview

As plants colonised drier terrestrial habitats, they developed water-resistant surfaces to conserve water, but these impede the movement of gasses - essential for respiration and photosynthesis - in and out of tissues.

A stomate is a microscopic pore on the surface of a leaf (or stem, petal or developing fruit) which facilitates the exchange of gases between the atmosphere and the inner tissues, but it's far more than a simple fixed opening. Because they regulate the movement of carbon dioxide, oxygen and water vapour, they're involved in several critical plant processes and therefore survival, growth and yield.

A "guard cell" lies on each side of the stomatal opening. The specialised cell wall architecture means that when the guard cells swell with water their shape alters. They pull apart, creating an aperture. When these cells lose turgidity, the pore closes.

Water loss through the stomata is a compromise the plant must make in order to photosynthesise (although this transpiration can serve other purposes). Unfortunately, pathogenic fungi and bacteria can sometimes take advantage of these openings to invade the plant, too.

The mechanism of stomatal function and how it's regulated is complex and the subject of ongoing research. Flux of potassium ions plays an important part. Stomata can respond to water supply, carbon dioxide concentration, light, hormones and the presence of pathogens. Stomata also exhibit circadian rhythm.

Typically, they open in the day and close at night, although some plants adapted to arid environments have a special way of collecting CO2 at night so that they can keep stomata closed during the day.

Another water-conserving adaptation seen in some species is the sinking of stomata below the main leaf surface and/or protection of the opening with hairs, to slow the rate of diffusion of water vapour.

Because the underside of the leaf is less susceptible to desiccation, it's not surprising that they are usually most concentrated on that surface on broadleaf plants. However, the number and placement of stomates typical of a species varies as an adaptation to its habitat. The floating leaves of some aquatic plants, for example, have stomates on the upper side. The environment in which an individual plant is grown (e.g amount of sun/shade) will also affect development of stomata.

Plants can undergo a certain amount of wilting and recover, but it should be realised that once the stomates close, there will be little photosynthesis occurring. This might be tolerable in the case of perennial landscape plants (and some desert-adapted species have special photosynthetic mechanisms to cope with this problem). However, it will be an issue when maximum yield and quality of vegetables, fruit and flowers is the goal.

Further reading:
15.2 Stomatal physiology Plants in Action, a plant physiology textbook available online at the UQ website
Gas Exchange Florida State University
Transpiration University of Hawai`i at Manoa
Stomata and pathogens A 2009 article from Plant Signal Behaviour
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