Short Cuts

Short Cuts in this issue:

Growing Grevillea from Seed

Early History of Callistemon Cultivation

Are You at Risk from Legionnaire's Disease?

Treatment of Pea-type Seed

The Ethics of Non-Indigenous Native Plants

Growing Grevillea from Seed

Over a period of time, we have found that in order to get best results with propagation of Grevillea from seed, we have made use of various tips mentioned from time to time in the "Australian Plants" journal.

1. It is best to try and use fresh seed, as it seems that the older the seed, the less germination occurs and seedlings are less robust from older seed.

2. Where possible we endeavour to peel testa from seed (the less damage to seed, the less chance of fungal problems and poor germination).

3. Individual seeds are placed between layers of sterilised "Cotton Wool", with cotton wool being kept moist (initially anyway) with water that has been sterilised by boiling, If germination is slow, we use "Previcure" to drench if signs of mould or fungus begin to show.

4. As soon as radicle begins to show movement, we individually transfer each seed to a separate tube containing very free draining sterilised sand/soil mix, and cover germinating seed with layer of sterilised coarse sand, one to two times thickness of germinating seed.

5. We endeavour to grow on seedlings in well lit areas, but out of direct sun to limit heating of soil in tubes, and try not to overwater.

6. In our area, early Spring, or late Summer, seems to be preferred times to propagate Grevillea seed.

It is possibly a little tedious, but at least by waiting until germination begins before actually planting seed in individual tubes, much better control can be given to hopefully getting a better final result.

From the SGAP Grevillea Study Group Newsletter; July 1993.

Early History of Callistemon Cultivation

European botanists and collectors of the late 18th century showed considerable interest in the plants of the remote southern continent of Australia. Callistemon citrinus was among the plants collected by Joseph Banks and Daniel Solander in 1770 during the discovery of the east coast of Australia. By 1788, three species from the Sydney region, C.citrinus, C.linearis and C.salignus, were available to English horticulturists. The convict artist, Thomas Walling, produced detailed illustrations of several Port Jackson (Sydney) species during the 1790s. An engraving of C.speciosus is published in a book published in France in 1813 which featured the plants growing in Empress Josephine's garden at Malmaison and was probably introduced by French botanists Leschenault and Labillardiere who collected seed, including C.speciosus, in Western Australia in the 1790s and early 1800s. C.speciosus was introduced to English horticulture in 1823. C.rigidus was introduced to English horticulture in 1815. Further introductions to English horticulture were:

• C.brachyandus - Introduced 1843, flowered, 1848. It was grown in the gardens of the Royal Horticultural Society from seed provided by Governor Grey of South Australia.

• C.citrinus (previously known as C.lanceolatus) - Introduced 1788.

• C.phoeniceus - Introduced 1843 from seed supplied by James Drummond from the Swan River District of Western Australia.

Callistemon phoeniceus usually has brilliant red bottlebrush flowers. This pink flowered cultivar known as Callistemon "Pink Ice" is becoming popular in cultivation. Select the thumbnail image or plant name for a higher resolution image (29k).

• C.pinifolius - Introduced from seed supplied by Allan Cunningham some time during 1820-1830.

• C.rigidus - Introduced to English horticulture in 1800. The original plant was collected by Robert Brown in 1800. Brown's description in 1819 was the first detailed taxonomic description of a Callistemon.

• C.lanceolatus (now C.citrinus) - Appears to have been introduced to Kew Gardens by Joseph Banks in 1788. Curtis commented that C.citrinus was common in nurseries around England. The report states that the original plant was grown from a "root sent from Botany Bay". It was popular in France and had been flowered there by 1800.

• C.linearifolius - Introduced in 1820 from seed supplied by Allan Cunningham.

• C.linearis - Introduced by Banks in 1788 when the species was first described as Melaleuca linearis.

• C.macropunctatus (now C.rugulosus) - Introduced in 1811 possibly from seed collected by one of the French expeditions to Australia.

• C.pallidus - Introduced in 1813.

• C.salignus - Introduced by Banks in 1788.

• C.viridiflorus - Introduced to England in 1818-1820. C.viridiflorus flowered in June 1824 and is still being cultivated as a greenhouse plant but there are reports that the plant is presently being grown outdoors by some Australian plant enthusiasts in England.

From the SGAP Melaleuca and Allied Genera Study Group Newsletter; March 1992.

Are You at Risk from Legionnaire's Disease?

For some time I have been interested in suggestions that nurserymen and gardeners were at risk from Legionnaires disease. I am considered to be an addict to black tubing micro-irrigation, so I was alarmed to see its use linked to the disease.

The danger of spread of the infection appears to be from the initial spray of water after it has been lying in tubing after periods of non-use. From time to time in the winter or after wet weather, take off the end stop of the tubing and allow the water which has been standing to run out. As most of us only water our Australian native garden when absolutely necessary, this precaution would seem most advisable.

I was very interested to read the following article by Maurice Haenke, editor of the Newsletter of the SGAP's Sutherland Group (Oct '94) -

"Following a recent radio news item concerning the possible implication of potting mixes in some cases of the potentially fatal Legionnaire"s Disease, I have tried to obtain some information from medical authorities, with the following results:

1. The NSW branch of the AMA referred me to its Queensland branch, which apparently was the source of the radio report.

2. The Queensland branch provided a copy of a Media Release issued on September 8 by The Australian Lung Foundation, of which the following is an extract:

   " ... The Australian Lung Foundation (ALF) sees it necessary to reissue a warning to the Public regarding the disease and how it can be avoided ... The ALF describes potential sources of infection to include any equipment that can produce aerosols (i.e. extremely fine particles dispersed in the air.

   CooIing towers, warm water systems and spas (whirlpools) have been associated with this disease. Commercial potting mix has been found to be a significant, however easily preventable, cause of this disease."

3. Dr. Bob Edwards, National Chairman of the ALF, calls for stringent control measures to ensure regular maintenance of these man-made systems. He also warns the general public to exercise simple precautionary measures in handling potting mixes and pay attention to the customer information detailed on all potting mix bags, in order to avoid potential health hazards. For further information, please contact Dr Bob Edwards, National Chairman, ALF, Te1(07) 870 4511. Dr. Edwards orally gave the following specific advice:
   Keep the potting soil wet
   Don't throw it about
   Use a mask and preferably use gloves
   Be sure to wash hands.

4. A spokesman for Sydney Area Health Service confirmed that some potting mixes had high Legionella counts, and were a probable cause of some infections, which were the subject of court cases. Users of potting mixes should use a mask and take care in handling, including washing hands after use.

From the Newsletter of the Association of Societys for Growing Australian Plants (ASGAP); June 1995.

Treatment of Pea-type Seed

I thought I'd pass on a new method I'm using to treat Acacia and pea-type seed prior to sowing. The typical treatment, of course, has been to pour boiling water over the seed (preferably after removing it from the plant), and let it stand overnight. While that method has stood the test of time, I have encountered several disadvantages with it. So often I've done the boiling water bit and then forgotten all about the small bowl that I put on top of the kitchen cupboard until cross-examined by Carol, my wife, as to its whereabouts. By then the seed has gone to pulp. If, on the other hand, I remembered to salvage the soaking seed, another problem arose.

After pouring off the water, the time comes to extract seed, one at a time from the soggy mass. Tweezers are ideal, but I can never find a pair. So I resort to using fingers. For me it's just about impossible to pick up one wet seed from that soggy mass. I always get at least two on the tip of my finger. Assuming for a minute I managed to get one seed on the tip of my finger, I would then place it over the position I want it in the seed-raising tray.

A slight shake of the finger does nothing to extricate the seed. A harder shake, and still the little bugger's on the tip of my finger. Harder still and the seed flies off, falls to earth I know not where, except that its definitely not in the tray and I can't find it. Is there little wonder I've been looking for a better method?

Probably I read about it somewhere. Basically, it's the sandpaper method (where the impervious seed coat is abraded by rubbing between two sheets of sandpaper....ed), but an improvement on the one-at-a-time, de-tipping your finger method. I got a small plastic container (Carol hasn't noticed it missing yet) and lined it internally with a coarse grade sand-paper. This simply involved cutting the sand-paper to fit inside the circular sides of the container (about IOcm) as well as on the bottom and inside of the lid, and gluing the pieces in place. A few months ago it underwent trials with the seed of Cassia/Senna artemisioides. I shook the seed in the container for a couple of minutes and that was it.

It was a delight handling the dry seed; even when I picked my nose the seed didn't stick to my finger! What was an even greater delight was the extraordinary rate and extent of the germination. The only problem now is whether to own up to the misappropriation of the plastic container. But it couldn't be used for anything else now, because even if the sand-paper is removed there's still all that glue inside!

From "Blandfordia", the Newsletter of SGAP's North Shore Group; July 1995. The comment of the Newsletter's Editor seems relevant...."Thanks Brian. Remind me not to shake hands with you anymore!"

The Ethics of Non-Indigenous Native Plants

For some years now I have been growing more concerned about the number and range of non-indigenous native plants that I and most other nursery owners have been selling to the public. We already know that Acacia baileyana, A.saligna, Grevillea rosmarinifolia and Pittosporum undulatum are now serious environmental weeds in many areas of southern Australia. How many more potential environmental weeds are nursery owners selling each year?

Having sold our nursery "White Gums' and purchased 500 acres of partially degraded hilly granite country south of Stawell, I have 'fallen in love' with indigenous flora. The superb natural swathes of bronze and green Kangaroo Grass, Themeda triandra; the drifts of flowering Soft Spear Grass, Stipa mollis when backlit amongst granite boulders: the discovery every week or two of a new orchid or some other grassy woodland species for our block: these are but a few of the excitements of discovering our own indigenous flora.

That does not mean that I have lost interest in our non-indigenous flora - far from it. In several areas near the house which were badly degraded by rabbit warrens I have established large collections of grevilleas, banksias and rainforest plants. However, I am the first to admit that they definitely look out of place. Even though they are Australian, the shades of green in particular just don't look right. As a result, we are planting a buffer of indigenous species around the edge of all non-indigenous plantings.

The results from these indigenous plantings have further opened up my eyes to the great benefits of indigenous versus non-indigenous plants. The non-indigenous plants generally have required watering, mulching and even applications of iron chelates to get them established. In contrast, most indigenous plantings have shot away, with species such as Banksia marginata reaching 3+ metres in 3 years and flowering for the last two years!

My wife Jane has always favoured indigenous plants and now I am beginning to appreciate her wisdom. As environmental consultants we were recently employed by the Department of Conservation to carry out a botanical survey of McDonald Park near Ararat, Victoria. In this beautiful grassy woodland remnant, local Field Naturalists had planted many species of non-indigenous native plants during the 1950s. Today a large number of these are not only still alive but are spreading far and wide throughout the park. We have identified over 50 species non-indigenous to the park: of these over 40 are spreading, many at an alarming rate! Who would think that species such as Acacia prominens, Acacia schinoides, Baeckea virgata, Callistemon rugulosus, Grevillea dimorpha, Grevillea aquifolium, Hakea laurina, Calytrix sullivani, Callitris rhomboidea and Micromyrtus ciliatus, to name but a few, would become weeds when planted in other parts of our country? Probably the worst two weeds in the park are Grevillea rosmarinifolia and Acacia howittii for they are hybridising with local indigenous species: unless all parents and hybrid offspring are destroyed quickly, then in a number of years there will probably be no pure Grevillea alpina or Acacia paradoxa in the area!

As a result of this survey there are a number of plant species that I will NOT be planting on our property. However, getting back to my original statement, we don't know what potential weeds we are growing in our gardens at present. As growers of native plants we should all be responsible with our plantings - any plant which you notice seeding freely throughout the garden should be noted and reported in SGAP newsletters.

Most of what I have said applies primarily to gardeners who adjoin or live in or near the bush - it is these areas where ants and/or birds etc can most easily spread the seeds of non-indigenous plants. However, as a group interested in promoting and preserving the Australian landscape, I believe it is essential that we discover and use our indigenous flora around all boundaries and areas that can be seen from adjacent roadways etc so that we retain the intrinsic and unique natural character of the particular area in which we live. Only when we can use our indigenous flora to give the impression of the natural bushland can we really call ourselves good Australian landscape gardeners.

From the Newsletter of SGAP's Garden Design Study Group; November 1995.

The Society for Growing Australian Plants