Bad Plants

The plants that are listed in the following pages as ‘bad’ plants mainly come into that category because they can become invasive. In other words if they are left to their own devices they will take-over the area, smothering the native plants, and eventually become the only plants in that locality. Many of the plants have escaped from the local gardens and have arrived in the dunes as prunings, such as from garden hedges, which have been dumped illegally in the dunes. Plants such as mirror bush (coprosma repens), buckthorn (rhamnus alaternus) and aloe (agave americana) are typical of this category.
Other plants arrive in the dunes as seeds which have been eaten by birds and then moved elsewhere in the bird droppings. Plants such as bridal creeper (asparagus asparagoides) and olive (olea europaea) are typical of this category.
Some plants such as the western coastal wattle (acacia cyclops) and the coastal tea tree (leptospermum laevigatum) were introduced as revegetation plants by earlier generations because they seemed to do well here. Unfortunately they did too well and they have now become an invasive menace. Each of these produces a massive seed crop each year which is loved by the birds and thus becomes reseeded else-where. Also it has been found that although they are easy to eliminate by cutting, there is always a host of seeds waiting under the tree to ger-minate as soon as the parent has been removed. Thus it is essential to have a regular follow-up of the site to hand-weed the seedlings.
The sea rocket (cakile maritime) and sea spurge (euphorbia paralias) which are prevalent on the beaches are listed in this book as ‘bad’ plants because they are aliens. However they are worth retaining in sensitive areas because they are very good for sand stability and dune retention.
Although much of the above sounds like bad news, the good news is that experience has shown that in many cases a massive revegetation program is not necessary because the seeds of many of the natives are also waiting to germinate under the shadow of the invader. When the invader has been removed the natives often reappear anyway. The sea-berry salt bush (rhagodia candolleana) is typical of this situation and it has often reappeared as if by magic as soon as the area around it has been cleared.