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Short Cuts

Readers are invited to submit short items of interest about Australian plants to be included here. If submitting non-original material (eg newspaper or magazine cuttings), please also advise if the author has given permission to republish and, if not, please provide a contact address so that permission can be sought.

Short Cuts in this issue:

Cuttings in the cold

How to look after cuttings during the winter months.

Tiliqua scincoides in my Garden

A new and rare plant? ....not quite!

Growing ferns from spore

It's not as difficult as you may think.....

Ivory Curl

Funny name for a spectacular small tree.

Our Unique Kangaroo Paws

Anigozanthos....a very distinctive Australian genus.

Plant Death in Pots

Water repellence of the potting mix may be responsible for plant failure

Cuttings in the cold

Being Shakespearean one could say, "Now is the winter of our discontent."

In short is it worth carrying cuttings through the colder months? The answer in an ordered world where cutting material is available within a day or two, is a resounding no. However in the world of the Australian Plant Society with its short and long excursions taking place mainly in winter months, exchanges between members interstate, once only visits to fellow devotees far afield, and never to be repeated excursions to an area in which a plant unique to that area exits, the answer must be that if the material is available at any time in winter, it must be taken advantage of.

And just how cold is too cold? Provided the cuttings are sheltered under glass or plastic, temperatures down to 5°C have no ill-effect and a variation from that temperature up to at least 26°C during the day does no discernible harm. In Sydney the winters of 1992 and 1993 were mild and sunny and cuttings took root during the winter months. In 1994 with many less sunlight hours very few cuttings took root (in a cold system) during the same period.

It is to be noted that many West Australian plants grow strongly in winter and the same could be said of many New South Wales Proteaceae. Many of the Asteraceae family make suitable wood in winter and provided the light is good, striking rate is often better than in summer when the soft herbaceous material is more inclined to rot from excess humidity. Which leads me to the rhetorical question....so what's the problem? And the answer - the cuttings just sit and some will become so unthrifty that when they finally strike will fail to survive when potting on. But as they say in the corporate world there is also an upside and this comes in the need for less care - no misting, far less watering, no losses in sudden hot spells, the use of larger cuttings with more leaves - and from this happy combination less fungal, algae and mildew problems. Simply it is a matter of holding on until Spring.

If you need to cut down attention time for the fortnight winter holiday, the cutting mix could include more coconut fibre (or peat) and the box cover taped down to exclude drying air. Boxes may be put into the sun during this period for at least half the day.

So don't toss out unrooted cuttings in June, keep setting cuttings and carry them through to warmer weather when they will strike.

Tiliqua scincoides in my Garden

Tiliqua scincoides? No, it's not a new and rare plant species that has recently been discovered, it's just the common old ordinary bluetongue lizard! I have been prompted to write this article by the appearance of one - no two, perhaps even three! - of these lizards in our garden. As I didn't know a great deal about them (or their habits), I decided to do a bit of reading up, and, for those who are as ignorant as I was, this is what I found:-

Eastern (or common) Bluetongue Lizards (Tiliqua scincoides) are members of the skink family (Scincidae) and are commonly found in areas of bushland around Sydney, and indeed much of eastern and northern Australia. These lizards are found in coastal areas as well as parts of the less arid interior. They are diurnal (as opposed to nocturnal) and feed on a variety of insects, snails, slugs, carrion, wildflowers (!), native fruits and berries. During the night they apparently shelter in hollow logs or under ground debris. Unlike most reptiles, and in fact many lizards, bluetongues give birth to live young, with up to 25-30 (but usually between 6-20) in a litter. They are the largest skink found in Australia (along with the Land Mullet), growing about 12" (30cms) in length (and sometimes longer). They are slow-moving but apparently can give a painful bite if provoked. The following advice was given in one book I read*..."If bitten, it is unwise to attempt to drag the hand from the lizard's mouth as this will rip the skin, whereas the lizard will eventually release its grip and although this may be painful it is a lot less damaging"!

Their greatest enemies in suburbia are dogs and ... lawnmowers! (I hope none of ours are unfortunate enough to meet this fate.) Initially I worried about the neighbourhood cats attacking them, but so far at least, they seem to pretty much ignore them. It appears that the bluetongues are big enough to look after themselves, and as they are generally quite slow moving, don't attract much attention (no prospect of a good chase I guess!). Like other skinks, bluetongues can lose their tails if necessary.

Bluetongue lizards will take water from wherever it is available....even from a cat's water bowl! Select the thumbnail image or plant name for a higher resolution image (28k).

I have wondered at the fairly recent appearance of these lizards in our garden, and believe it is probably due to two main things: the lack of predatory birds (especially kookaburras) in our gardens; and the presence of a source of water (mainly water that collects in the saucers under our many pots. I have observed the bluetongues thirstily drinking water from these on several occasions. In addition, we certainly have plenty of places for these lizards to hide, with lots of rock crevices and a good deal of leaf litter in our back garden.

The only other less-than-common lizards I have noticed in our garden are the leaf-tailed geckos, which are nocturnal and rather shy, so sightings of these are much less frequent.

From the February 1998 issue of the newsletter of the Warringah Group of the Australian Plants Society.

Growing ferns from spore

Generally spore propagation is easy, the following is a simple version of how to grow practically all species of ferns from spore in the home.

The Mix: I use a 50 - 50 mixture of fine cut peat moss and gritty,washed sand as the base mix. The addition of charcoal up to 1/4" (6 mm) is beneficial. To two litres of dry mix in a larger container, pour one litre of boiling water over the mix and cover with a plastic wrap. Then sterilize the mix using a 700watt microwave for 12 minutes.

Containers: I use 500g margarine containers, washed in hot, soapy water and then soaked in 10% chlorine bleach and dried. Label the containers and fill with a level 10 mm of mix. Allow the mix to cool a bit and only use fresh mix.

Add the spore: The easy way to gain an even spread of the spore is to add the spore to a small amount of water in a small plastic spray bottle, shake and spray on to the mix, although this may add too much water to the container. Another method is to use a knife, picking up the spore and tapping the knife so as to evenly spread the spore. I then cover with two layers of plastic wrap secured with a rubber band.

The spore sacs (or sporangia) on the undersurface of a fertile frond on Todea barbara. Select the thumbnail image or plant name for a higher resolution image (34k). Photo: Fred Johnston

Where to grow it: Place the container in a dry warm, well lit position out of direct sunlight. Check for drying out, about monthly in summer and two monthly in spring and autumn. Add small amounts of boiled water if the mix is drying out, by spraying gently with a fine mist.

What you are trying to do: The spore will grow into a small green prothallus. On the prothallus, but unseen, will grow an archigonium (female) and an antheridium (male). If the humidity and temperatures are correct, the sperm in the antheridium will swim through the moist areas of the prothallus and fertilize the female egg in the archigonium.

How long?: It may take from weeks to months for the green prothallus to appear. Sporelings may take six weeks to six months to develop or even longer.

Pricking out: When sporelings are from 1/4 to 2" (6 - 50 mm) high they can be gently removed, either by using a sharp knife (to tease apart the roots) or tweezers, and placed into their next growing medium.

Mix for potting on: I prepare the same two litres of mix as before and add 1/2 litre of perlite and 1/4 litre of 1/4" (6mm) diameter charcoal. Small containers are used for potting on...up to 2" (50 mm) diameter.

Growing on: At this stage the small plants are kept under controlled conditions, i.e., under glass or plastic. This is the time I fertilize them with a high nitrogen fertilizer, say, N.P.K. of 20-14-18.

Hardening off: After the sporelings have grown on, you can harden them off slowly by opening the container a bit at a time and exposing the plants to the outside atmosphere. This, I find, is safer in the spring or early autumn away from the extremes of the heat and cold. The plants can be repotted into 70 - 100 mm pots when they are approximately 50 - 80 mm high or if roots are seen growing out of the bottoms of tubes.

From the December 1998 issue of the newsletter of SGAP's Fern Study Group. For further explanation of the life cycle of ferns, see the Australian national Botanic Garden's Fern Propagation Page

Ivory Curl

Buckinghamia celsissima (Proteaceae) is endemic to North Eastern Queensland and is a most attractive and hardy rain forest shrub or small tree and until recently was classified as a monotypic genus. However it seems that another species exists as a variant but little is known of this other form.

B.celsissima (ivory curl or spotted silky oak), if grown as a specimen or garden plant, becomes a smaller ornamental which is suitable for most situations. This characteristic enables it to be planted in small gardens where it can be pruned quite heavily if desired. New growth is pink, red or bronze.

The plant is a reasonably quick grower and accepts most soil conditions and thrives accordingly in sun or part shade. Although susceptible to heavy frost when young this hardy plant will tolerate mild to moderate cold conditions. B.celsissima has no known predators when healthy conditions prevail.

The inflorescence of Buckinghamia celsissima. These are conspicuous and make a spectacular display. Select the thumbnail image or plant name for a higher resolution image (41k).

The foliage is dense and in cultivation is retained to ground level. Juvenile leaves are light green, paler on the under side and trilobed towards the apex. They may measure 30cm by 8cm. The mature leaf is entire and may measure 15cm by 5cm (note that these measurements are given for plants in vigorous growth).

The species appears to be of normal branching habit. The bark on the trunk is rough, brown and persistent. A mature specimen in Toowoomba has developed six trunks measuring 10cm at DBH (Diameter at Breast Height) and reached seven metres in 15 years of growth in close competition. Another younger specimen in an open situation in half sun flowers copiously and is a superior medium garden shrub measuring 3 metres by 2 metres. Better conditions such as deep red soil (ex volcanic), acid soils, good sunny situations and plentiful moisture greatly enhance this shrub/tree for good growth and superb flowering.

Inflorescence

Dense terminal racemes, 10 to 20cm long smother this plant in mid summer, a glorious sight which persists - par excellence - for many weeks. No wonder it is so aptly dubbed the "ivory curl flower." The flowers are sweetly scented and attract birds and insects alike.

Reproduction can be achieved from fresh seed or cuttings, but not without some difficulty. Mature seed is usually produced in April-May.

This adaptable plant can be used for parks or street planting and can be grown as far south as Melbourne.

From the January 1999 issue of "Native Plants for New South Wales", the newsletter of the Australian Plants Society (New South Wales).

Our Unique Kangaroo Paw

Mention Anigozanthos and most people would have a blank expression on their face, but if I said "kangaroo paw" instead, most would instantly know what I was talking about. These unusual plants are an outstanding part our very unique native flora. Contrary to popular belief they can be very hardy if the right varieties are selected and planted in the correct position in your garden.

The first step to growing kangaroo paws successfully is selection of the hardier varieties. Basically any hybrid which has Anigozanthos flavidus as one of its parents and has bright green foliage, not greyish-green or grey, is most likely to succeed. Below I have mentioned hybrids which seem to be suitable for gardens in humid climates as well as some which you should be careful of. Also mentioned is flower height (which varies greatly), while foliage of most paws only grows to about 60cm.

Anigozanthos flavidus is the hardiest kangaroo paw. Flowers are usually yellowish green but other colours can be found. (53k).

Tried and tested are a series of kangaroo paws called the 'Bush Gem Selection' most of which I have found to be successful. The 'pick' of the selection would be "Bush Dawn" (lemon-yellow, 1.5m), "Bush Sunset" (red, 1.5m), "Bush Noon" (bronze-orange, 1.5m), "Bush Gold" (lemon-yellow, 1m) and "Bush Glow" (orange, 1m).

Some old favourites of mine which are usually harder to obtain but have very rich colours are "Red Cross" (deep burgundy-red, 1.2-1.5m) and "Big Red" (bright red, 1.5m). Best of all must be "Yellow Gem" which has vivid yellow flowers on stems up to 1.5m high.

Kangaroo paws to avoid in humid summer areas are "mini paws" which definitely haven't proven hardy, with the exception of "Mini Princess" (also promoted as "Bicentennial Kangaroo Paw"). This is a hardy plant which has short, pink-red flower stems throughout much of the year.

Most kangaroo paws flower in winter/spring. When selecting varieties a tip is that the shorter flowering plants usually flower earlier in the season, and the taller later. For a longer display of flowers a clump of each can be planted together.

Correct positioning is the second factor in growing kangaroo paws. They must be planted in a very sunny position (at least half a day full sun all year), well drained soil is also important, although hybrids cannot tolerate extreme dryness. When planting make sure you don't plant the clumps too low in the soil or have mulch piled up around their leaves as this will cause rotting.

Maintenance is extremely easy. In the first year or two you will only have to remove dead flower stems. As the plants grow older it is a good idea to trim back the foliage to about 20cm high after flowering is finished.... most people use hedge clippers or their "whipper snipper" for this. Older plants can also be divided in autumn if you wish to place clumps in other parts of your garden. When dividing I have found bigger pieces of the clump more successful.

From the July 1998 issue of the newsletter of SGAP's Far North Coast Group.

Plant Death in Pots

It has been my experience that a main cause of death of plants after purchase and soon after planting is water-repellence in the potting mix in which they have been grown. Most of our pine bark-based potting mixes are slightly to considerably water-repellent at the time of manufacture. This water-repellence is caused by the coating of bark particles with waxy secretions that are a natural by-product of fungi that are using the bark as food. Many potting mix manufacturers add what is called a ‘wetting agent' to their mixes to overcome water repellence. Wetting agents are detergent-like organic compounds that have the same effect on the wax coatings as does dishwashing detergent on a greasy frying pan. The coatings on the bark particles are dissolved by the wetting agent so that water can fully wet them.

Some potting mixes have little or no water-repellence at the time of manufacture, but they can develop it while plants are growing in the mix. But even if wetting agent had been added before potting, its effect declines over time (about six months) as it is washed from the container and as microbes decompose it.

Water-repellence has been a major cause of poor plant growth in nurseries, but it is also a major cause of deaths and poor early growth after planting out.

This is how it happens.....So long as a mix that has water - repellent properties is kept wet, the water-repellence will not be expressed. So when such mixes are irrigated frequently and are not allowed to dry out at all, there is no evidence that the mix is in fact prone to repellence. But if the mix is allowed to dry down to about the point at which a plant would soon begin to wilt (as may occur at a Sale), some of the particles in it dry to such an extent that at the next irrigation they remain dry. The irrigation water simply runs past them.

After several cycles of drying and only partial rewetting, an irrigation that appears to be effective can leave most of the mix quite dry. This is, I believe, a major cause of deaths of recently-bought plants. Irrigation that is less frequent than that used in the nursery or grower’s backyard could produce the sequence of events described above. If irrigations are frequent enough to prevent death before planting, water repellence can still rear its ugly head after planting out.

Potting mixes are generally of coarser texture than soils. When a rootball is placed into soil, the surrounding soil sucks water from the rootball, so causing it to contain less water than when it was sitting on gravel or a bench in the nursery. Until new roots grow out into the surrounding soil, the plant is still totally dependant on the diminished amount of water in the rootball. For a week or so, irrigation must be more frequent than had been necessary in the nursery. Even if the mix of the rootball is not water-repellent, if irrigation is less frequent than at the nursery, there is a real possibility that the plant will wilt and die in warm weather. But if the mix is water-repellent, the combination of less water in the mix because of suction into the surrounding soil and the retention of little irrigation water once the rootball mix has dried, can lead, in a few days, to death through drought.

A further consideration in this is that if the top of the rootball has been buried under soil that is finer than the potting mix within the rootball, it is not possible for water to enter the rootball until all of the surrounding soil has been saturated with water. Only then can the pressure of the water in this saturated soil force some water into the rootball. It cannot flow in 'against gravity' into the coarse potting mix.

Of course freedom from disease and hardening off are essential to good post-sale performance, but I believe that attention to water-repellence is also critically important.

This leads me to two conclusions. One is that all plants sold at SGAP sales should have wetting agent applied to them just before they are taken to the Sale. This is standard practice with the millions of seedlings that are produced annually for plantation forestry. I am aware that some growers already do this. I believe that it should be mandatory that, in the interests of maximising customer satisfaction, this be done by all growers.

The second conclusion is that our customers should be instructed not to bury the rootballs of their plants. The top of the mix is to be at the soil surface.

From the August 1998 issue of the newsletter of the South Australian Region. Kevin was responding to a member's letter on death of plants soon after purchase.

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Australian Plants online - March 1999
The Society for Growing Australian Plants