Our next wild pollinator count is on again in April. Pollinators in autumn?! Yes, spring and summer are generally when we think of wild pollinators. But they are around in autumn too, and they will be looking for plenty of resources to build their nests and provide for the next generation. Is your garden ready?
Flowers, the obvious first step!
- Many online pollinator flower guides are for northern hemisphere gardens, so most recommend plants that are not native to Australia. But most of these flowers are still great for attracting wild pollinators here, especially fragrant herbs like lavender, salvia, coriander and basil.
- If you prefer a native garden, the Rural Industries and Regional Development Corporation has released a free-to-download guide to planting for pollinators. It is aimed at honey bees but is also relevant to wild pollinators, and provides handy information on seasonal flowering times and regional differences.
- Plan flowers for every season, so your garden can sustain pollinator populations throughout the year. Also choose modern hybrid varieties carefully, as some have been bred for quantity (size and fullness) not quality (nectar and perfume).
- Plant a riot of colour! There is no single best colour for pollinators, as different insects have different levels of colour vision, and other factors like nectar and flower shape also determine whether a pollinator visits.
Pollinators don’t just feed on flowers.
- Wild pollinators need alternative sugar sources when floral nectar is in short supply. Some plants, particularly Fabaceae (e.g. Acacia) species, have extrafloral nectaries that produce nectar through glands in plant stems. Tree resins and sap flows are also popular with native bees and wasps – social stingless bees use the chemical properties of many native tree resins as a defence against predators and pathogens. Honeydew is another important sugar source for many stingless bees and wasps – it is not a plant sap, but actually a sugary substance secreted by some aphids and scale insects as they feed on trees.
- Wasp and fly pollinators also have additional benefits by being natural enemies of insects that damage our food and ornamental plants, like aphids and beetles. So don’t stress if you find aphids on your roses! Just make sure you have some natural enemy attracting plants growing nearby.
- Some pollinators, particularly butterflies, bees and wasps, need salts in their diet. This is why you often see them feeding on damp ground, muddy puddles, and animal remains or poo. You can create a muddy area in your garden and mix in a bit of sea salt.
- Water is essential. But remember insects can’t swim as well as birds! A small, very shallow pool, with plenty of debris to help them climb out if they fall in, is better than a bird bath or pond.
- Pollinators also love rotting fruit. They will rarely pierce the skin themselves, but if it has split naturally or through bird damage, they will find it. Some people put overripe fruit from the kitchen out in the garden to attract pollinators and add nutrients to the soil. But this is not recommended if your region suffers from fruit fly or European wasp invasions!
Avoid or limit chemical use.
- Neonicotinoids, in particular, can have lethal effects on honey bees, wild pollinators and other non-target insects. Residues of these chemicals can be found in any part of the treated plant, including the pollen and nectar that pollinators feed on, and remain in the soil for months, having long-term effects on ecosystem function. Neonics are sold under a variety of different names by most of the major chemical companies – have a look at the active ingredient listed on your spray bottles if you’re not sure. Table 1 (page 13) in this APVMA report lists the main neonicotinoid compounds on sale in Australia.
- Other chemicals, like herbicides or fungicides may seem harmless to insects, but can have indirect effects. Herbicides remove many of the ‘weedy’ plants, like dandelions, that pollinators rely on when other flowers aren’t available. And they don’t just affect plants – if they combine with insecticides in the environment, they can kill insects too. Fungicides can also interact with other chemicals in the environment – they can increase the susceptibility of honey bees to hive parasites, but their effects on Australian wild pollinators are mostly unknown.
Pollinators need a place to call home.
- Insect hotels are great for trap-nesting bees and wasps and are very easy to make. There are plenty of design ideas online, or you can be creative and drill holes in old tree branches or wooden furniture. Also try your local men’s shed or TAFE, as some groups are already making insect hotels for community projects.
- Only about 15% of the world’s bee species nest in dead wood cavities. Most of the rest are ground-nesting. These species prefer to dig nests in bare, sandy soil that is not compacted and preferably on a slope of at least 30°. But don’t clear vast swathes of soil! Not only with this increase erosion, it reduces the availability of other pollinator-friendly ground covers, like flowering herbs and leaf litter.
- Leaf litter would probably not be your first choice if asked to create pollinator friendly habitat. But it can be just as important as flowers, as it provides all-year hunting habitat and an overwintering shelter for predatory flies and wasps.
- A sustainable pollinator garden has year-round resources for pollinators, and is managed to have minimal impacts on pollinator health. In particular, nesting and overwintering resources available in autumn will mean more pollinators emerging the following spring.
If you would like to read more, have a look at these great resources: