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Re-establishing local bushland in suburban Melbourne
Beryl and Trevor Blake
The interest in bush regeneration and habitat establishment has prompted us to write of our efforts to regenerate local bushland and create a garden on a site that had retained a bushland infrastructure but had been degraded by the grazing of two horses and inappropriate planting.
18 years ago our family moved to East Ringwood (20km east of Melbourne) to a 1 hectare site with great potential. Our land is on the north side of the second highest hill in the metropolitan area. Some large Pinus radiata were along the western boundary and a mixture of eucalypts provided a canopy that helped to deter frosts. Indigenous species are Eucalyptus melliodora, E.obliqua, E.macrorhyncha, E.cephalocarpa, E.goniocalyx and E.cypellocarpa with some other tall species which provided sheltered windbreak to the site - Acacia dealbata, A.howittii, A.longifolia, Exocarpos cupressiformis (Native Cherry) and some fine examples of Kunzea ericoides and a closed canopy of Pittosporum undulatum.
The horses had been gone 5 years and there had been areas of little damage or a regrowth of local species which we liked encouraging. However, there were plenty of invading species present - blackberry, privet, holly, ivy, loquat, coprosma, boneseed, wandering jew, cotoneaster, rampaging honeysuckle 10m into trees, periwinkle and the unkillable agapanthus. These we removed but we still get the seed of a number of these species being spread by birds.
Around the house we quickly established in existing beds a wide range of colourful plants and removed many of the exotics that we didn't really need to live with. Birdlife was quite good with a resident rufous fantail being a highlight. Spring always brings the mobs of demolishing yellow-tailed black cockatoos who absolutely delight in ripping open thick branches of Acacia longifolia for the prize - a very large wattle goat moth caterpillar. These wattles have now all been removed from the scheme of things and all seedlings pulled.
|"The trees that were doing this of course were, and still are, real pests -|
Of the 12 x 1ha blocks on the north side of Wambalano Park most have now been subdivided into various sized blocks over the years. One to the north of us, with almost untouched bush, was flattened by an insensitive subdivider which left our place receiving far more wind than ever before - the midstory trees we realized were vital to break the wind and protect the taller eucalypts. The trees that were doing this of course were, and still are, real pests - Pittosporum undulatum. Individually they have a lot going for them. Our strategy has been to remove them from key positions and replace them with protective species.
With the light blocked by areas of pittosporum, nothing grew below and this suited the experiments which followed. We were concerned that if we opened up too much we would be swamped with weeds. The area where we selected to remove an enormous pittosporum was virtually sealed from all direct weed invasion by shrubbery and yet would receive plenty of sunlight. We were fascinated over the next two years to see the regeneration of local species - the seed was still there and viable. The richness of the stipas, poas, microlaena, lepidosperma, danthonias, lomandras etc and subsequently with lilies, glycine, pultenaea, hardenbergia, platylobium, acrotriche. Some little gems appears too, droseras, orchids and brunonia.
Hardenbergia violacea is a colourful and common climbing plant in eastern Australia. Select the thumbnail image or plant name for a higher resolution image (35k).
This provided great incentive and our curiosity was aroused to see what we could do. Our neighbour's property on the south side was pretty rich in local species and had been deliberately left undisturbed by a very sympathetic owner. We have used existing pittosporums in places to provided a 'seat' from weed species while we tried our version of the 'Bradley Method' on a large scale. It has worked, with pittosporum and Acacia longifolia gradually being removed to allow in light. Careful attention has been applied to these areas as they are regenerating, particularly in the first couple of years until the seal of the bare ground is well on the way with indigenous flora. Removal of any weed species has been carried out quite regularly and I regard this as vital to success. The western boundary has a strong screen of pittosporum which takes full brunt of the frequent howling westerlies. In the upper story here are several very large Pinus radiata which marked and old boundary line. East of the property are healthy examples of stringybarks, some stipas/poa grassed areas and a healthy patch of Gahnia sieberana.
Gahnia species are perennial herbs often found in areas subject to periodic inundation. Select the thumbnail image or plant name for a higher resolution image (51k).
From the house to our northern boundary was a sea of very vigorous large pittosporums - most of these have now gone and microlaena grassland/lawn drops down to a water area where Gahnia sieberana, microlaena, Melaleuca ericifolia and Acacia melanoxylon seem to be thriving below the overflow. A wide range of waterplants was established and three species of frogs have gravitated to shriek throughout the night after rain and when the temperature is satisfactory. The pool deliberately has no fish and the tadpoles are in their thousands with no mosquito larvae apparent. Occasional visits are made by white faced heron and little pied cormorant to feed on the tadpoles and check out the food potential. Microlaena and danthonia are strongly colonizing the areas of overburden from the pool extraction. We also transplant these species as they germinate in unwanted areas each year.
Since the removal of some pittosporum an area of Kunzea ericoides (Burgan) has established itself and will be restricted in its spread. Many Exocarpos cupressiformis have begun to appear - these showed no sign of regenerating for the first ten years or so. Many nesting boxes have been placed in trees and possums of course, have moved into some, eastern rosellas, galahs and gang gangs have bred and we have sugar gliders feed in a very large Eucalyptus obliqua. A perfect sighting of a powerful owl was had in 1995 where we gawked at each other for over half an hour at 2am. This remained in the area feeding on possums whose chilling screams shattered still nights as the ringtails were dismembered. A tawny frogmouth is in residence and can be seen in the fork of a dead tree, sunning.
|"....chilling screams shattered still nights as the ringtails were dismembered."|
The incentive for including a pool was the appearance of wood duck with their chicks on our swimming pool. They had been visiting for several years with the occasional visit of a pair of black duck. Encouraged by Paul Thompson and his enthusiasm for water in the garden, we literally took the plunge and the focus of the garden has changed and been remarkable. Someone commented that it's like sitting around a fireplace in the garden. The life that it has attracted is a constant source of enjoyment. The mayflies and dragonflies are hatching at the moment (November). Both species of duck are constantly weaving in amongst the trees and landing on the water, wattlebirds dive for the insects, the butcher bird is never far away and the odd tadpoles provide food for their fledglings. A magpie family breeds in a large eucalypt and they parade around whilst a pair of mudlarks probe the banks of the pool. Last year we produced 32 ducklings and it's on again this year with 21 appearing so far. No birds are fed and as a result there is no expectation and trust has build up.
Butterflies and moths play on important part in the life of this regeneration project. Certainly the grasslands are developing to provide a food source for some caterpillars. Many other food plants are also present for larvae and garden beds with daisies seem to provide nectar for many adults. The large flowers of Leptospermum scoparium and the massed flowers of Kunzea ericoides are constantly frequented by skippers and wanderers.
Bluetongued lizards breed and shelter amongst rockwork, woodpiles and grass thickets. Warmer evenings have bats collecting insects from over the pools. On two occasions we have collected specimens and they are Goulds Wattled Bat and Lesser Longeared Bat.
Returning to the management. We inherited a large patch of angled onion weed which took 3 years to eradicate each and every bulb; this we achieved some years ago. Presently we are using the same technique to remove a most invasive bulb - monbretia - we estimate this will also take 3 years.
Another technique we used to prevent an invasion of weed from a neighbour through a wire fence was to transplant heavy outbreaks of microlaena and danthonia from where it was not needed (we had encouraged this for the purpose) and place the sliced off layers of 'good grass' along our boundary - it has come away so strongly that only an occasional weeding is needed.
Another method we tried on a steep slope was to cover the area with flat slabs of stringybark bark and then control the grasses - underfelt also works well. All this does is cut down the immediate bare earth which would not easily have held mulch. The bark will slowly break down but the cover will be established. We are about to continue this method over an area of winter grass that is on a boundary fence, but will cover the area with newspaper first so that this persistent and invasive grass will not re-establish. Sweet vernal and shell grass have been pulled each November when they 'show' themselves.
Flat weed broke out when the water are was created. Intensive weeding removed this problem and the occasional plant is dug out when noticed. Evergreen alkanet tends to invade grassed areas and is constantly removed along with common centaury and petty spurge.
An area where we wanted to establish ferns and rainforest plants was covered with a deep layer of buzzer chips - this certainly stopped all weeds and has supplied a great mulch depth and rich soil as it has broken down over the years.
|"The ferns were not looking vigorous at one stage so we removed some key pittosporums and let in light and the ferns responded magnificently."|
The ferns were not looking vigorous at one stage so we removed some key pittosporums and let in light and the ferns responded magnificently. All materials that is cut down or pulled is either mulched or composted but the real nasties are sent to the tip.
There is always plenty to do but the response of species indicates we are on the right track.
As a general comment on places where there is total weed invasion it is essential to cut seed heads before they ripen. We are of the opinion that spraying, heavily mulching over newspaper to prevent invasion of areas of remnant bush and then re-establishment of local species would be worth considering.
This article is reproduced from the June 1997 issue of the newsletter of the Victorian Region of the Society for Growing Australian Plants.
Beryl and Trevor Blake are long time members of the Society. Trevor is a talented botanical artist and is the illustrator for the "Encyclopaedia of Australian Plants" by Rodger Elliot and David Jones.
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Australian Plants online - December 1997
The Society for Growing Australian Plants