Mole Station Native Nursery

Gardening with native plants

1. Drainage

Many native plants require well drained soil. If your soil stays wet sometimes for weeks, it may be sensible to check out those plants which can withstand waterlogged conditions. These include melaleucas and callistemons and many eucalypts. A good guide is to note plants which grow happily along creek banks e.g. Eucalyptus camaldulensis (River Gum), Casuarina cunninghamiana (River Oak) or Callistemon viminalis (Weeping Bottlebrush).

For those plants requiring good drainage such as grevilleas or correas, it may be necessary to build raised beds or a mound on which to grow the plants.

As a general rule many native plants growing near the coast can withstand poorly drained soils and humidity, while plants native to the dryer interior prefer sandier well drained soils and a dry atmosphere.

2. Pruning

Usually native plants should be pruned after flowering though pruning a little and often is very beneficial. While small, tip prune each month or so to encourage a compact centre. Later, pruning once or twice a year may be all that is required. Most importantly, prune early to avoid bare ugly branches at the base of the plant.

Most eucalypts do not require pruning and naturally drop their lower branches as they grow. Pruning off these lower limbs may cause the tree to fall over.

3. Mulch and Weed Control

Many natives dislike having their roots disturbed, resulting in sudden death. The safest way to deal with weeds is to avoid them altogether, particularly around the base of the plant. Weed mat with a cross cut where the plant is to be planted is a good way to achieve this. Placing newspapers ten sheets thick around the plant and close to the trunk is also effective as a weed barrier. The next step is to cover with whatever mulch is to be used such as wood chips, hay or lawn clippings making sure the material is not actually in contact with the trunk.

In frosty situations, a thick mulch can actually increase the risk of frost damage. Ideally a good thick mulch should be applied in spring after the frosts have finished. The mulch then helps keep the roots cool and conserves moisture during the summer months but by winter will be thinner and more likely to allow the sun to warm up the ground.

For low maintenance it is advisable to mulch an entire area of the garden rather than around each plant. Mowing is simpler and it is easier to deter the grass from one large bed than many smaller ones.

Many natives do not compete well with grass growing close to the trunk.They become stressed and may succumb to diseases such as scale.

4. Fertilising

It is probably more important to feed the soil rather than the plant. Adding organic matter to the soil will supply natives with the nutrients they require without overfeeding. Over fertilising may result in root burn or over vigorous growth leading to plants which blow over easily. Blood and bone is usually beneficial when placed in the hole prior to planting. Beware of mushroom compost as it may be too alkaline, many natives preferring an acidic soil with a pH between 5 and 6.5. Most natives resent high levels of phosphorus resulting in a yellowing of the leaves. To correct this it is necessary to apply an acidifying fertiliser, such as iron sulphate or iron chelate. The following is a useful recipe for natives which have yellow growth tips and/or dying leaf edges and will also give them a boost:

2 teaspoons iron sulphate

2 teaspoons magnesium sulphate (epsom salts)

2 teaspoons ammonium sulphate (Granam)

mixed together in a large watering can (10 lt.)

Iron induced chlorosis (as this condition is called) may also be the result of too much water, so avoid extra watering.

5. Water Requirements

Some idea of the natural environment of the plant will indicate whether supplementary watering is required or not. Here are a few tips:

  • if the plant has broad glossy green leaves it is likely to originate from a rainforest or wet sclerophyll situation.
  • plants native to watercourses e.g. callistemons and melaleucas enjoy extra water.
  • most grevilleas do not require additional watering once established
  • plants with grey or narrow leaves often originate in arid regions
  • many natives will cope with extra water as long as the drainage is excellent.

6. Pests

It is important to plant a range of different native species to attain a balance of bird species. A lower storey will provide shelter for smaller birds such as honeyeaters, finches and silver eyes. Prickly grevilleas, while providing shelter for small birds, also provide food and nesting areas. They are very efficient at keeping insect pests under control.

A plant which is stressed will often become a target for disease including scale and associated sooty mould. A spray of white oil and malathion will provide temporary control but improved growing conditions such as increased drainage or mulching to prevent weed competition may be a more enduring option.

In areas where scarab beetles (e.g. Christmas beetles) attack eucalypts it may be simplest to plant those eucalypts which are not so palatable such as Eucalyptus acaciiformis or E. parvifolia.

Some compact melaleucas and leptospermums are susceptible to the webbing caterpillar which lives in a web inside the shrub and may ultimately defoliate the plant. Check these plants frequently and pull out the webs or use a systemic insecticide.

7. Frost Protection

Many of the smaller native shrubs and creepers including boronias, hardenbergias and kennedias naturally grow in situations sheltered by taller trees. Though in full sun they often thrive, winter frosts may kill them. If planting in an exposed situation, the following suggestions may help:

  • 3 stakes with a white woven fertiliser bag thrown upside down over the top is an efficient frost guard. It may be left on all winter as the material breathes and some light does penetrate
  • a smooth ground surface around the plant is better than ground mulched high with hay etc. keeping the plants well watered helps prevent serious frost damage
  • spray plants with Envy® frost protectant before winter
  • seed harvested from a frosty region will definitely produce hardier plants ˆ mulch in spring and not shortly before winter
  • frost damage with a wood chip mulch is less than with a hay mulch
  • frost damage with a dark coloured mulch is less than with a light coloured mulch.

8. Garden Design

Though garden design is of course only limited by your imagination, the following suggestions may help with the practicalities of deciding which plant to put where:

  • have plants with similar requirements together e.g. plant grevilleas and banksias together in a well drained sloping position. The melaleucas and callistemons will cope with the heavier moister soils.
  • it is usually more important to position contrasting foliage types beside one another than contrasting flower colours
  • small shallow bird baths may be placed near dense shrubs to provide protection for small birds
  • the use of large stones and logs beside the plants give not only a natural look but also provide a cool root run
  • do not plant prickly plants near paths or gateways
  • when constructing a mound a depression in the centre will help with water absorption.
  • including native grasses and reeds will help give the garden a natural appearance.

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