Friday, September 28, 2012

Native Wisteria

Callerya megasperma  (Milletia megasperma)
Just as those glorious, non-native wisteria are coming to the end of their flowering period, the native wisteria  is starting to open its softly furry white buds.
Like the introduced plant, this is a large woody climber, needing a strong fence, a sturdy pergola, or a large “wheel” on a post,  for its support. It also has large panicles of flowers, though does not produce quite such a generous display of them.
Unlike the introduced wisteria, this is an evergreen plant which keeps its glossy green leaves all year round. The stems of young plants are particularly beautiful, with their peeling bark.

 The flowers are interesting, in that the reproductive parts are clearly visible. Note here the female part, the long slender style topped with a little stigma, and the male parts, the stamens, each with a pollen-producing anther at its tip. The anthers of this flower are joined together at their bases.

Native wisteria flowers are rather unusual. Flowers of the pea family typically hide their reproductive parts between the petals of their keels, and have a high rate of self-pollination. This flower clearly wants to get its pollen out there, and its stigma is firmly placed where it will receive pollen transported from another flower, when it is visited by its nectar-seeking pollinator.

Here’s a detail I didn’t notice until I had this photo up on my computer!

It’s a butterfly caterpillar, from the family Lycaenidae. These butterflies have a symbiotic relationship with ants, which protect them in exchange for sweet juices, which the caterpillar exudes. I'm not certain which species of butterfly this one is, but it may be a pencilled-blue (Candalides absimilis). (This is a species known to breed on Callerya. and the caterpillars seem to me to look right.)

The plant will have  has a second ornamental feature around Christmas time, producing large, woody seedpods, which look as though they’re covered in soft green corduroy.

Native wisteria is a plant of rainforests which grows happily in Toowoomba gardens, tolerating light frosts, and needing no extra watering in our climate.

Friday, September 21, 2012

New England Daisy Bush

Olearia canescens
Here’s a plant that we don’t see much of, yet it was probably once quite common on black soil hills on the Darling Downs . It’s a pretty, waist-high, daisy bush, also known as “grey daisy bush”, because of its soft grey-green leaves.

I photographed these flowers, from a bush which has almost finished flowering for the year, on a roadside at Silverleigh, near Acland.

The plant (hard to photograph among other plants) had obviously flowered profusely, so when a friend told that it grows easily from cuttings, I took some home to try, as it makes a good garden plant.She has one in her garden, where it fills a space more than a metre wide, and says it is best pruned each year after flowering, to help it keep a neat shape.
I took these photos of the same species at Tregole National Park, out near Morven, last month.

This is a drought resistant, frost hardy plant.

Saturday, September 15, 2012

Grow Me Instead

Here’s a great website. Have you had a look at it?
To find the Darling Downs Section, click on the map of Queensland and go on from there.

Narrow-leafed Croton

Croton phebalioides
I was shown this lovely stand of old-growth shrubs last weekend, at Silverleigh (near Acland).

As the photo shows, they were growing on a basalt scree-covered hillside. It was an eastern slope, which I suspect would be a favourite habitat, as this plant likes to be sheltered from wind and sun when it’s young.
Usually found on the western side of the Great Dividing Range, this aromatic, grey-foliaged plant is a cousin of the better-known silver croton, C. insularis.

Like that plant, its leaves have silver backs, which look lovely blowing in the wind. Also like the silver croton, each leaf turns a startling shade of orange before dying and hangs on for some time. The plant is ornamented with bright flecks of colour almost all year round.

This plant was in bud. Flowers and the fruits are inconspicuous, but much appreciated by wildlife - particularly birds, which eat the seeds.

The top photo illustrates the plant’s natural, unpruned shape, when grown in the open. I have never seen it used in a garden, but suspect that it would make a very good, waist-high hedging plant.
It is fast-growing, very drought hardy, and (considering its natural habitat), probably tolerates at least light frosts.
For more on Croton insularis, see articles July and Dec 2009.

Those Mysterious Leaf-glands

We are all aware, (at least I think we are), that plants produce nectar in their flowers to attract pollinators. These are usually insects, though some plant species use birds or other animals.
The glands which produce it are called nectaries. They are surrounded by a beautifully engineered arrangement of petals, designed to ensure that only those capable of carrying pollen to other flowers can reach the nectar - and then only if they align themselves just as the flower requires. (Flowers are bossier than you'd think!)
This means that the pollinator body-part, which gets dusted with pollen in one flower, will then be correctly positioned to deliver it to the appropriate bit of the next one. It has to be deposited on the stigma, to do the job of fertilising the flower’s future seeds.
Somewhat less known, however, is that plants have other nectaries which are open to all comers. They are called “extra-floral” nectaries - “extra” as in Latin for “outside”.

They can be on various parts of the plant, but a common position is at the base of the leaf. Croton species provide a good example, with their little glands visible to the naked eye (provided it has good eyesight, or has its specs on). Here they are on Croton phebalioides...

 ...and here on Croton insularis.

Such an easily accessible source of highly nutritious nectar could be found by all sorts of tiny creatures, but a common result is that the fiercest will discover it and keep it for themselves,  chasing away (or eating) potential rivals. In this way, the plant attracts protectors, usually ants, which help to keep it safe from other little sap-sucking, leaf-biting creatures.
Isn't that just so knacky?

Saturday, September 1, 2012

Toowoomba’s Oldest Tree?

Ficus rubiginosa  (Ficus obliqua var. petiolaris)
Toowoomba botanist John Swarbrick has drawn my attention to this magnificent tree. It is a “Scrub Fig”, and can be found in Meredith Crescent.  
 This part of Toowoomba was once part of the garden of Carl Hartmann (1833 - 1887), a noted Toowoomba botanist, explorer and nurseryman who is now best known for his involvement in the establishment of our city’s original Botanic Gardens in Lindsay Street.
Hartmann cultivated 22 of his 40 acres, creating a magnificent garden of his own which contained plants from all over the world. It became a favourite destination for Toowoomba’s weekend picnickers. There was even a bus service which brought people from town for their pleasant day out. Some of the specimens he planted can still be found in the streets and private gardens in that part of Toowoomba.

The fig is an unusually large one of its kind, so it’s more than likely that it was a mature plant at the time Hartmann cleared the land. Much change has happened around it, including a lowering of the soil level. The tree still stands on a mound which would have been the original height of the ground.

Growing in the tree are several large, old blood vines Austrosteenisia blackii. Which probably also pre-date European settlement of the area.

Most of their little leaves are up in the canopy, mixed with the larger leaves of the fig.

However the odd few sprout lower down, and have enabled us to identify the vine, which still grows naturally in Redwood Park, and may have once been common in the Toowoomba City area itself.

Blood vines produce large panicles of deep red flowers in late spring. They would be a sight worth seeing, on such a large vine as this one. We must keep an eye out for them!
Meanwhile, the tree is producing a large crop of figs, which will provide a feast for our native birds.