Saturday, September 27, 2008

Pretty Pink Darling Peas

We have two local Darling Peas which are easy to mistake for each other. Both are very pretty, easy-to-grow garden plants, and both have the typical Swainsonia seedpods, which begin green, and develop a pretty pink blush on their sunny sides. The mature pods make good little boats to amuse children if weighted with a tiny pebble below the waterline. Ankle-biters with plenty of puff can have boat-races by blowing them across puddles. 
Swainsona galegifolia
This is a multi-stemmed sub-shrub , with a clump of stems growing from a single crown.
A well-grown plant can have several dozen stems, about waist-high, and branching. Each stem lasts a few years, but the plant is constantly being renewed by new stems, and has a few flowers for much of the year. Tidy gardeners will cut off the old ones each season.
 This drought-hardy plant is uncommon in our local area, but is found on the edges of rainforests, and grows particularly well in red soil. 
Swainsona queenslandica
The Darling peas we usually see on, red and black soils around Toowoomba are this species. A very drought hardy plant, it spreads by underground rhizomes, and is the plant we see  around Toowoomba. Its unbranched stems only grow to about 30cm high. It is very easy to grow from a piece of rhizome such as the one below. (My little finger marks the point at which the stem appears above the ground.)
This plant looks its best if it’s cut back to the ground each year after the spring/summer flowering season.

If well-watered this is a vigorously spreading plant. People with tidier gardens than mine might like to have it contained by paths or buildings. Others will see it as a good plant to naturalise in a rough, or perhaps occasionally-mown, area.

It is my favourite, being very showy at this time of year, and looks great mixed with yellowtop daisies, native geraniums, and native poppies.

Distinguishing Between the Two
Swainsona galegifolia and Swainsona queenslandica can be easily confused in the wild, because their flowers and leaves are rather similar.

Swainsona galegifolia's stems grow in a clump from a single crown.
 Swainsona queenslandica has isolated stems, separated along its creeping underground rhizomes.
The difference is obvious in well-grown plants. However, in a rather skimpy plant with few straggly stems it can be difficult to know what's going on underground.
The distinction is clear, however, if the plants are in flower. The wings are distinctly different in length.
  Swainsona galegifolia's wings are not more than 60% of the length of the keel.

Swainsona queenslandica (below)has wings which are about the same length as the keel, or a little longer.
 Locally, it has both red and pink forms.

Tuesday, September 16, 2008

Bright and Pretty Yellowtops.

Senecio pinnatifolius var. pinnatifolius (Senecio lautus subsp dissectifolius)
It is being a very good year for these attractive local daisies, which are coming up all around the district without any help from humans. They make very good garden plants, and grow easily from seed - so keep your eye out for some that you can introduce to your garden, both for their colour, and their potential to attract butterflies.
They are  very frost and drought hardy needing no watering once established, and flower from early spring to Autumn, with strong flushes in both those seasons. I find they look their best if they’re cut back after both these seasonal flushes.
This would be an excellent waterwise species to use in our district as a bedding annual.
There are a number of Australian yellowtop species. This is the common one around Toowoomba. It’s an upright little perennial, about 30cm high and broad, with a slightly woody stem. It can be scraggly in dry paddocks, but in good garden soil has fairly dense mid-green foliage and makes a neat round shape. Most of its wispy leaves are very finely divided, to the point where no part of the leaf is more than about 1mm wide.
A little further west, from around Oakey, we also have the rather similar Senecio brigalowensis, a somewhat coarser annual. Its leaves are also "dissected", but relatively with a similarly deeply divided leaf. Its leaf-parts are broader than 1mm.

Do they poison the Horses?
Many good native plants are less appreciated than they deserve, because they have an unfair reputation for deadliness to stock.
Yes, Senecios do contain poisons, and eating too much of them will kill stock. However, reports of senecio poisoning by Australian senecios is rare. There are two reasons. One is that no single plant contains much of the poison, and a bit of a munch does the animals no more harm than we suffer when we eat plants with similar poison levels such as mint, basil, or parsley.
The other is that animals don’t like the taste, and won’t eat it if anything more palatable is available. It is probable that most of the reports of “seneciosis” in Australia have resulted from stock being left in badly overgrazed paddocks . You can see some examples of these on the western margins of Toowoomba. In normal, well-managed pasture, yellowtops are dotted about amongst the other pasture plants. In seasons like the present, there might be a lot of yellowtop (photo at left), but a season which favours yellowtop growth also favours good growth of pasture grasses, so there’s plenty of healthy food for stock to eat.
In seriously overgrazed paddocks, however, all the edible plants get been eaten out by the poor, miserable stock, which would rather eat absolutely anything but yellowtop. With all competing plants so thoroughly removed , the paddock becomes covered in a carpet of yellow daisies, and woe betide any poor neglected animals that are left with nothing else to eat.
(It is this carpeting effect, which causes some people to claim that this is a rampant plant which will take over your garden. It doesn't.)
(Reference “Poisonous Plants of Australia”, Selwyn L. Everist, Angus and Robertson. 1974)

But don’t Grow Madagascar Fireweed.
Senecio madagascariensis
This is a non-australian plant that has become a major weed in Australia. It is just beginning to creep into our district. It is still much less common than our local native yellowtops, but could become a threat to them.
It is an aggressive coloniser, definitely a threat to stock, and could drive our local lookalikes to extinction. This could happen simply because it seeds more vigorously and takes over habitat - but there is another threat, in that people mistake the local plants for Madagascar fireweed - often calling them “fireweed” as well - and weed them out. The natives are much more easily exterminated by this method than is the interloper, as the natives have one major “crop” a year, in spring, while Madagascar fireweed can produce six generations in this time, continually re-seeding from spring to autumn.
Learn to tell the difference, and make sure you weed out any intruders - but do leave the natives in their place!
It is only mildly difficult to distinguish between them, despite the fact that they are all variable plants, with some overlap in their characteristics.

Like our local yellowtops, Madagascar fireweed is a rather upright plant, but distinguishing between them is usually a simple matter of looking at the leaves, and making allowance for the fact that the leaves of all the species are rather variable. All can have some toothy-edged, lance-shaped leaves, and some deeply dissected leaves. However almost all the leaves of the local yellow-tops are deeply dissected, and only leaves on the very young plants are lance-shaped and tooth-edged. By contrast, S. madagascariensis has almost entirely lance-shaped leaves with toothed edges, with just some of the older leaves around the base being deeply dissected.

A further clue can be to count the involucral bracts. These are the long narrow green bits, pointy at one end (with a little brown dot on the point), which together form the involucre - the little green “cup” in which the flower-head sits. For me, essential equipment is: a pin (so I don’t lose my place); another pin (to point with); and a good pair of reading glasses. Senecio madagascariensis has 19-21 (usually 20-21) of these bracts.
S. pinnatifolius var pinnatifolius usually has 13, though it sometimes has more. If the flowers on your plant have fewer than 19 bracts,  this confirms what you probably already knew from looking at the foliage - that it is the native species.

Counting the bracts won't help distinguish S. brigalowensis from  S. madagascarensis, though, as it has about the same number. To distinguish these two, you need to look a bit more carefully at the leaves. S. madagascarensis leaves have teeth along the edges. S. brigalowensis has pointed lobes, longer than the width of the central part of the leaf.
Another difference is that S. madagascarensis is is rather easy to pull out of the ground, unlike S. brigalowensis which has a deep tap root, making it difficult to pull up.
So. It's important not to grow Madagascar fireweed - but it's also important not to go overboard, exterminating perfectly good native plants on suspicion. Quite apart from being pretty wildflowers, an ornament to our landscape, they are also (like every component of any natural environment), an important part of the web of life. Some insects depend heavily upon them. Birds depend on the insects, and so on. We should never wantonly tear at the fabric of our local web.

Some Spring-flowering Climbers.

Two of Australia’s most gardenworthy climbers are in flower at the moment. You can pick them out from the road, by their conspicuous whitish flowers.
One of them is the native Clematis (see January article)

The other is Wonga Vine Pandorea pandorana.
These plants are named for Pandora, the poor woman who, according to ancient Greek legend, is responsible for all the world’s troubles. She was given a box and told not to open it. Well, what would you do? She opened it of course, and out spilled the troubles, like seeds from the pods of the Pandorea vines. (They always blame the women, don’t they? I have always suspected that Eve was pressured!)
Wonga vines are popular garden plants. They are so attractive that some people are surprised at being told they are native!!!

They are robust woody twiners which have masses of small bell-flowers in spring. They come many colour forms throughout Australia.
Our locals have creamy-white flowers, and are some of the best. Even locally there are variations, with some being larger (as at right), and some having yellower throats (below).

Wonga vine’s natural environment ranges from rainforest to dry scrubs. It is frost hardy, very drought hardy, and happy in full sun, (though it grows better if the roots can be kept cool under mulch, or in shade). When it has nothing to climb on it forms a mad, tangled shrub, and we often see it in this form in paddocks, and places where the local rainforest has been cleared.
As with most Australian plants, wonga vine’s lifespan is not well-known, but you can count on at least 25 years and probably much longer.

Thursday, September 11, 2008

Carnival of Flowers, Toowoomba.

Toowoomba’s annual carnival starts next Friday (19th September), and goes for a full week.
Do make sure you visit the Australian Plant Show, put on by the Toowoomba Society for Growing Australian Plants Stall. They will be selling a huge variety of native plants at low prices. It’s being held at the TAFE horticulture building, behind the Cobb & Co Museum in Lindsay Street.
The TAFE Gardens, particularly those at the Horticulture building, should also be seen. They make skilful use of native plants in a landscaped setting.
Don't forget to visit the both the orchid societies' displays as they always have native as well as introduced plants. You can often pick up some bargains there.
And do go and look at the prizewinning gardens in the native plants section. They should be particularly good this year, after the rain we’ve been having.

Open Garden at Helidon

and Native Plant Sales
There's a new event on Carnival Saturday - next Saturday 20th September - which will interest lovers of Native Plants.
Helen Howard, of 62 Helendale Drive, Helidon Spa is opening her garden for the day. She has a lovely garden featuring rare plants, but especially Grevilleas. I expect it will be a mass of beautiful flowers.
Helen is also hosting a native plant sale on the day, with a number of stallholders selling their native plant wares. This is an event not to be missed!
Helidon is twenty miles east of Toowoomba, an the highway from Brisbane. Helen's home is in
Helendale Drive, which is west of Helidon proper, between it and the Helidon Spa. The street leads directly off northern side of the highway, and its name can be clearly seen from there.
Contact : Helen Howard Tel:46977418 Mob: 0447 199 462

Dwyers Scrub Conservation Park

I was shown a new place to look at plants, this week. Dwyers Scrub at Rockmount (South east of Toowoomba) has a lovely patch of semi-deciduous vine scrub on basalt soil. It contains a very interesting and rich variety of dry rainforest species which are a delight to see, and one of the reasons why the area has been declared a reserve. (The other is that it is a habitat for the rare black-breasted button quail.)
I was particularly taken with the bottle trees. We most often see these trees out in the open, either as planted specimens or as remnants left when an area of scrub is cleared. While they can be very attractive - or interesting, depending on your point of view - they are nothing on the “real thing”. Here is a tree looking comfortably at home. Its graceful shape has been influenced by the plants growing around it which have caused it to reach for the sky, and it has a number of epiphytes taking advantage of its rough bark.

Fat Bottles, Thin Bottles

Brachychiton rupestris
Perhaps we planters of trees can learn a lesson from the bottle trees in Dwyers Scrub.
The familiar trees with grossly swollen trunks are usually seen where they have obviously been planted and grown in the open. The trunk shape appears to be the result of the trees’ situation since infancy - though the amount of water the trees are given may also contribute to an eventual fat-trunked silhouette. There may also be some genetic variation. Who knows, now what has caused the difference between “Darby” and “Joan”, the well-known trees on the highway at Hampton.

When I planted bottle trees in my own garden twenty years ago, I set out to try to produce tall, slender “bottles”, by surrounding them closely with shrubs. I appear to have succeeded. Contrast my tree (right) with a nearby footpath specimen of about the same age (below), which has already developed a figure distinguished by portliness. Busting out of its britches, isn’t it? It’s a pretty tree, but not my preferred figure-type.
Bottle trees grow well on all our local soils, tolerating a great range of drainage and pH types. They are drought, bushfire, and frost resistant.
They sometimes drop some of their leaves in late winter, having a rather thin canopy for a month or two until the new leaves grow in spring. They rarely drop them all, but as you see, my young tree, which has never done it before, has made a thorough job of its first leaf drop!
Gardening fashions of the last century and more seem to have aimed at obliterating all signs of local character in our built landscapes. So many suburbs, all over the western world, look much like any other suburbs. How disappointing to go overseas and find ourselves walking down streets that could have been in our own home towns!
So I love to see it - wherever I am, and whatever the local plants - when gardeners and local councils have put in plantings that say firmly “this is OUR place, and it’s unique and special”.
Bottle trees say this, most emphatically.

Pick out the Red Cedars from afar.

Toona ciliata
Our district’s most famous timber tree, the red cedar was always the first to be cut out of an area, often cut by specialist cedargetters who took no interest in any other type of tree.

The cedars are easy to find in spring. Having lost their leaves in winter, they put out a characteristic flush of new red leaves at this time of year. They can be distinguished from the general green of the rainforest canopy, and targeted from far away.
We can still pick them out, both in our suburbs and in the bush, in the same way. The technique is sometimes used by modern thieves, often woodwork hobbyists, who see nothing wrong in plundering the public estate for their own personal use. Sadly roadside red cedars are likely to disappear mysteriously. This is such a pity. The grand trees of which should be our children's heritage are often made into trivial bits of "woodwork" valued for a few years then discarded.

Sunday, September 7, 2008

Comments on Nestboxes

Further to my June article on hollow trees for wildlife, reader Dylan has added this comment:
I was wondering if people out there have more info on nestboxes for wildlife? I have made 5 so far and plan to make many more. But, before I make more I wonder what others have done and what works well in your experience in terms of size of box, entrance hole size and location, materials used, height in trees, etc etc.
Are there good websites out there or blogs that I should know about? I haven't done much searching yet, so if anyone knows of one or a list of them, please do share. (I will then add my photos too..)
Nestboxes are not something I have tried. Are there any readers have experimented with them, and can give us some helpful tips?
Do you have any residents in your five boxes yet, Dylan?

Thursday, September 4, 2008

A good local native for hedges.

Hedge Orangebark
Denhamia bilocularis (Maytenus bilocularis)
Spring brings us flushes of pretty new leaves on many native trees and shrubs. This wild plant was responding beautifully to some heavy pruning (implemented by the cows over the fence).
It  has been suggested as a good native replacement for those photinia hedges we see springing up all over the place because of its equally pretty show of red leaves.
It won’t grow as fast as a photinia, but once established, a slower-growing plant does have a considerable advantage as a hedge, in that it is more easily kept to a neat shape.
Hedge orangebark will, if left alone, eventually become a small tree, and can grow as an understory plant. However, it makes such a good dense screen if grown in full sun and kept pruned, that this may be the best way of using it in a garden.
It has the additional attractive feature of yellow, bird-attracting seed capsules in late summer.
Faster growth would certainly be achieved with watering and fertilising - but like so many of our local natives, this plant can survive and look good through the heaviest drought, with no watering ever again, after its first few months in the ground.