Selecting Native Plants to Support Birds and Bees in Suburban Perth for a Healthy Productive Environment.
Why do we need pollinators? Most of the food crops you can think about need pollination to produce fruits or vegetables for our kitchens. The list of bee-pollinated crops is huge and if bees were not doing their job the consequences beggar the imagination. Fruits we would not be able to enjoy include apple, citrus, plums, peach, papaya, persimmon, strawberry, avocado, chestnuts and almonds. On the vegetable front how would life be without tomatoes, celery, broccoli cabbage, onion, potato, cauliflower, zucchini and many types of beans? Adding flavour to our cooking would be a problem without coriander, chilli, allspice, caraway, fennel and cardamom. And who could even start each day without a cup of coffee. All of this would be idle chatter if bees were not in so much strife worldwide.
Western Australia is recognised as a diversity hotspot across the globe’s Mediterranean climate areas with over 13,000 species of plants, which call the state their home. In contrast the British Isles cannot pull 2000 native species together.
This local treasure chest of biodiversity is also under threat from a lack of pollinators. This enormous diversity has come about through aridity, low carbon soils and a lack of either glacial or volcanic activity to add mineral nutrients. The relationships with pollinators include some of the most extreme and bizarre examples anywhere on the planet. Here marsupials, birds, bees, beetles, wasps, moths and even emus have a role in this reproductive task.
Why is there a lack of pollinators for our wildflowers? Perth has lost 70% of its green cover since settlement in 1829. By 2050 it is expected we will loose a further 3%. This is habitat destruction on a huge scale. There are currently 60 local plant species classified as endangered.
What can we as home gardeners do about this? I can see two strategies here. One is to find alternative ways to control pests. The second is to attract more birds, bees and insects to our gardens by deliberately choosing pollinator friendly plants.
First up we need to fundamentally change the way we approach garden and household pests by foregoing biocides. What is a biocide – anything that kills life. This includes chemicals that are used to “control” insects, diseases, nematodes and weeds. Major consequences of this form of chemical warfare are many unexpected outcomes.
Neonicotinoid insecticides were developed in the 1990’s because they appeared to be safer for birds and mammals than organophosphate and carbamate insecticides, which were in common usage at that time. Neonics as they are often called, are today the most widely used insecticides in the world. Recent reports have raised concerns that these have contributed to honey bee colony collapse disorder (CCD) a major problem for bees across the globe.
Insecticides are generally indiscriminate and kill off the beneficials as well as the target insects. Bee health is affected by exposure to a wide range of agricultural pesticides.
How can we grow food and ornamental gardens without biocides? A new approach is needed. Some alternative concepts include exclusion netting to keep pests such as cabbage moth, Mediterranean fruit fly, thrips and mites away from vegetables and fruit. Some low-tech solutions I have seen include wood ash sprinkled over cabbage plants to deter cabbage moths, coffee grounds spread around the vegetable patch to deter snails and slugs from crossing the barrier and petroleum jelly spread around the trunk of citrus trees to stop ants from spreading scale insects.
The second strategy of planting pollinator friendly plants in our gardens is rich with exciting possibilities and can be approached at many levels.
I have recently completed a revision and update of the Waterwise Plant list on behalf of the Nursery and Garden Industry of WA for the Water Corporation of WA. The online descriptions of 650 plants indicate which are attractive to birds, bees, insects, even small lizards and possums. This list will be easy to access through the Water Corporation website www.watercorporation.com.au and is expected to come online in September to replace the current database.
Beginning a pollinator friendly garden could simply consist of choosing appropriate plants from this list and planting these in your garden. Embracing this concept fully might see you developing a planting list that covers all four seasons of flowering. This is quite challenging for mid summer and mid winter when there are less plants in flower. Also while its fine to have plenty of tree canopy cover, if there is not an understorey and ground cover, many birds will be reluctant to enter, roost or nest because the garden lacks protection and places to hide.
Natives versus exotics. In my view there is no war here, just added opportunity. Grevilleas are superstars in the bird attracting business because they are nectar producers and many species have flowers across a number of seasons. At home we have winter flowering red hot pokers and a selection of aloes that flower heavily during winter, a time when there is not much happening with local natives. Bees and nectar feeding birds constantly visit these flowers.
There is a very strong case for protecting existing native trees in urban areas. A study of one old jarrah tree in Kings Park revealed a level of visitation that is almost incredible. This one mature jarrah tree supports 83 species of native animals, birds, reptiles and insects. Not a tree but a condominium. By way of contrast wind pollinated European trees don’t have to attract wildlife to achieve pollination.
There are lots of benefits to us as gardeners from a garden filled with birds, bees, insects and native animals. We can enjoy a new soundscape and gardens come alive with movement. It’s also very comforting to know that we are helping the web of life to prosper in our suburbs. Studies have revealed that our own sense of wellbeing and mental health are considerably enhanced by contact with nature; and what better place for this but our own garden.