Mallee Native Plants » Caring for Native Plants

Banksia Cultivation

Corinne — Mon, 19 Jun 2006 13:52:00 +0000

I have come to the conclusion that once the temperature reaches 0C that it doesn’t matter how much lower it gets. Cold is cold! We should be thankful, I suppose, that at least the temperature increases during the day to being quite pleasant, and of course with the intense cold we get these beautiful blue sky days.

The information on Banksias is truly incomplete. Many books will state categorically that particular species will grow only in acid soils. Until they are grown in soils of different pH and tested, we do only have this information to rely on.

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Banksia sp.

I have updated this post with a photo of a Banksia I would like to grow at home. This one is at the Arboretum where pH is closer to neutral.

One of my aims is to try a variety of Banksias, using additional sulphur if necessary. I originally wanted to grow only those plants which grew well in highly alkaline soils. The problem is that I want to see good growth on all the plants and want to intervene if necessary. I will still have the restriction of rainfall to contend with any way. Record keeping is the key to making this a useful exercise.

I certainly want to have Banksia coccinea and Banksia menziesii in the garden.

Frost and Seaweed Products

Corinne — Thu, 15 Jun 2006 08:12:03 +0000

Theoretically, the frost finishes tomorrow until the next bout! Another beauty today had me trying twice to get out of our driveway without the windscreen icing over.

Yet everythingÂ that I am growing is looking ok, amazingly. I must say that I have a ‘nasty suspicious nature’ when I read such things asÂ ‘frost tolerant, drought tolerant, lime tolerant’ etc. Until I have the evidence for myself, I am always wary of other people’s assessment of these qualities. Unless I know the geography of the area where a species naturally grows! Or I know the climate of a particular nursery eg. one from an area of high frequency of frosts that come with very low temperatures.

I have read various claims about seaweed type products improving the frost tolerance of young plants. Having read it, I thought I would deliberately try the products, not only for their usefulness in settling in new transplants but for this quality as well. I cannot say that I have set up a very scientific system of measuring this. I am more interested from the point of view of a home gardener as well as a nursery grower so it will be purely anecdotal.

Frost Hardy Plants

Corinne — Wed, 14 Jun 2006 12:51:45 +0000

This is the coldest winter we have had for a few years. Recently there have been 5 frosts in a row and this seems to be the pattern. Apart from 7.5mm last Friday there has been no rain so the potential for damage to plants is increasing as this dry weather continues.

It is a standing joke amongst Australian native plant growers that if it will survive in Canberra during the winter, it will survive anywhere. When we first moved here, the small publications published by the National Botanic Gardens were a bench mark for frost hardy plants.

Many more plant species have been available since these books were first published (from 1971), so the original list is quite small in comparison with what is known today.

The plants listed in Volume 1 are as follows:
Banksia ericifolia (Heath leaved Banksia)
Banksia marginata (Silver Banksia)
Banksia spinulosa (Hairpin Banksia)
Banksia serrata (Saw Banksia)
Banksia integrifolia (Coastal Banksia)
Banksia media
Banksia robur
Banksia baxteri
Eriostemon myoporoides (now Philotheca myoporoides) Long-leaved Wax Flower
Melaleuca wilsonnii (Wilson’s Honey Myrtle)
Isopogon anemonifolius (Drumsticks)
Goodia lotifolia (Golden Tip)
Acacia drummondii (Drummond’s Wattle) -needs protection from frost until about a metre tall.
Indigofera australis (Austral Indigo)
Grevillea baueri
Hypocalymma angustifolium (Pink-flowered Myrtle)
Boronia heterophylla
Melaleuca incana (Grey Honey Myrtle)
Micromyrtus ciliata (Fringed Heath Myrtle)
Westringea fruticosa (Coastal Rosemary
Thryptomene calycina (Grampians Heath Myrtle)

I will add to this list later and find more cultivation information.

Variegated Native Plants and Frost

Corinne — Sun, 28 May 2006 07:37:40 +0000

I am beginning to think that variegated plants are not as frost tolerant as their plain leaved relatives. The variegated form of Pandorea jasminoides looks a little the worse for wear at the moment. The upper leaves look ‘soggy’ compared to the older leaves and the plain Pandorea in the pot next to it has not been touched by frost.

A similar thing has happened to Correa ‘Dusky Bells’ variegated form. The plain form is as tough as old boot leather. The other consideration is that the potted plants are in more active growth than those in the ground and are producing new growth more often.

I hope it is just the new growth that is the problem, otherwise I am in trouble with the rule I set for myself. Plants I grow have to be frost hardy and relatively drought hardy, unless I choose to deliberately break this last rule, knowing that extra water will be required. The first rule is not negotiable.

I may have a management problem to overcome in the future as these plants are grown in the open.

Anigozanthos flavidus (Kangaroo Paw)

Corinne — Sat, 20 May 2006 12:49:00 +0000

I messed up the cutting when I tried to divide an Anigozanthos flavidus red flowered form. At least I hope it is red as the label states. The trouble is that if the plant is seed grown it could be green as this seems to be the dominant colour in this species.

Anyway I wanted to divide it so that I had extra plants should the main one meet with an accident, like being drowned or forgotten! The bits that broke off may have enough tuber attached to grow on.

Anigozanthos flavidus is the hardiest of the Kangaroo Paws, and has the tallest flower spikes, which seem to flower for a long time. Most of the ‘paws’ prefer well drained positions but this one is quite forgiving as it is hardy in most soils and positions. Seed germinates readily, especially if fresh. Divide during the Autumn before new leaves begin to grow. A heavy sharp knife is necessary with this species as it has a large tuber.

Lime Water and soil pH

Corinne — Mon, 15 May 2006 13:16:36 +0000

Having watered the young stock with lime water yesterday and given all the new transplants some seaweed solution, I went out to check on everything this morning. My imagination is probably too vivid, but those plants did appear to look happier. I will continue the lime water and seaweed solution next week and then do another pH test on the mix in the little pots. I feel quite hopeful that I have the solution to the problem.

The potting out seems to be never ending at the moment. There are so many pots of rooted cuttings waiting to be separated. The weather is cooling fast so I need to get them into their pots as soon as possible. Next week promises to be warmer and sunnier so hopefully all will work out and the plants will have a fighting chance.

There are seeds popping up in pots. It really is exciting when germination takes place. Some seed that I had give the hot water treatment to, I had forgotten about. When I â€˜foundâ€™ them some had sprouted. I had intended potting them directly into their individual pots but lack of time dictated the one pot and separate them later.

Using Lime

Corinne — Thu, 11 May 2006 12:53:06 +0000

I have discovered why my new Correa rootlings were not growing as they should. Other plants which like alkaline conditions were just sittting also, despite the warm weather we had. My potting mix is not the pH it should be. It is way too acid at pH 5.5. It was only after hearing the tale of woe of another grower that the ‘penny dropped’ and I realised that my problem was probably the same. A pH test on the offending mix proved that it was the same problem, although not as low as his was. He thought that Azaelias would have done excellently in his mix.

Solution? Keith watered his pots with lime water made with a teapoon of lime in a standard watering can. He had to do this four times altogether before the pH was an acceptable 6. I have had to do the same. I have also added a cupful of lime to a wheelbarrow load of the potting mix for new seedlings and cuttings. It goes against the grain to do this when the soil pH is 9+! However if it solves the problem in the potting mix and I get the growth on the plants then it is worth it. It has been so disappointing to see the losses and the unthrifty new plants. I was certainly thankful to be alerted to a new scenario for my nursery.

Non Toxic Sprays

Corinne — Fri, 14 Apr 2006 02:31:46 +0000

I have always been interested in using methods to deal with insect pests and diseases that did not involve toxic chemicals. Although, what is meant by that can be debated. After all when making sprays from such things as rhubarb leaves, which are poisonous, am I making a toxic spray or not?

Using pest plants seems to be a good vengeance on them. Also using readily available Australian native species seems to be good sense. Eucalyptus has long been used as a remedy for many ailments of humans. I came across the use of Casuarina (or Allocasuarina) needles to make a fungicide which is good for damping off fungus in seedlings, and black spot and powdery mildew on plants. Use any available species. These trees are often used in windbreak and border plantings.

One recipe is 10 grams Casuarina needles to 2 litres of water, boiled for 20 minutes. Stand to cool. Make this solution up to 10 litres with additional water and stir well. Strain through cheese cloth so that it will not clog the spray nozzle. Spray over and under leaves, and around the soil beneath the plant. This much will spray 100 square metres. See this ABC Gardening Australia Fact Sheet of a few years ago for other details.

Insect Sprays

Corinne — Tue, 11 Apr 2006 02:05:40 +0000

ABC TV’s Gardening Australia programme on the weekend had a session on controlling pests in the garden. It was good to see the recommendations demonstrated, rather than just being talked about. The presenter used an old toothbrush to scrape scale from the stem of plants, when there are not many insects to deal with. The other treatment was a homemade oil spray which smothers scale and kills the insects.

The recipe for this is 2 cups vegetable oil, 1 cup pure liquid soap. Whip together with a ‘stab’ type mixer or in a food processor until it is white. Store in a screw cap bottle, labelled with the contents. To use this, mix 1 Tablespoon of the solution in 1 litre (2 pints) of water and spray over the scale. Do not spray when the temperature is 30C or above as plants could be burnt.

Scale is carried around by ants, so deal with the ants in the garden as a first step to controlling scale on plants.

Aphids are another pest which ruin the growing tips of plants, and destroy flower buds. For strong stemmed plants, spraying a jet of water onto the leaves will dislodge the insects.

I am trying to find more suitable methods of dealing with insect pests in the garden than using some of the nasty sprays that are available.

More on everlasting daisiesâ€¦

Corinne — Sat, 08 Apr 2006 08:12:36 +0000

The Xerochrysms (Bracteantha, Helichrysm) mentioned before come in a variety of colours. The small hybrids range through shades of pink, yellow, gold, bronze and shades of wine red

One that I have begun to grow I bought in as â€œRed Hybridâ€, the result of breeding, and the seeds come true to colour. I would say that the seed of the flowering plants in the home garden may produce some surprises which I will know about soon! These daisies do interbreed and throw back to originals, but are fun to sow and grow on because of the diverse colourings.

Fertilisers suitable for Australian native plants promote good growth in these plants. In general, Blood and Bone types, and slow release granules are recommended, but I suspect that any good organic fertiliser would do the job with these too. As with most gardening, taking the time to prepare soil, add fertiliser and make decisions about watering will bring the best results.

The main pests seem to be green caterpillars which you donâ€™t find until great chunks have been eaten out of the leaves. Remove by hand if you can find them, rather than resort to sprays. I have also found at certain times of the year that aphids gather on the growing tips. These will distort the flower buds if you do not do something to control them.