Bee finding nectar on a Grevillea flower

Insects play a hugely important role in our ecosystem: as vital pollinators of plants, including important food crops; as prey for birds, bats, amphibians, reptiles and other creatures; as predators for destructive insects; as helpers in breaking down decaying matter in the environment; and, in some cases, controllers of weeds. Along with changes in weather patterns (particularly an issue in tropical climates), other causes of insect decline include loss of their habitat caused by deforestation, conversion of land to intensive monocultural agriculture and increasing urbanisation; use of pesticides, especially neonicotinoid chemicals that are harmful to many insects; overuse of nitrogen fertilisers in farming, which pollute the wider landscape and reduce biodiversity amongst plants, enabling only a few dominant species to prosper; and the use of herbicides that have destroyed various wild food sources for insects.

Bee foraging on a bloom of Hydrangea aspera Villosa Group

Bee foraging on a bloom of Hydrangea aspera Villosa Group

Unlike some other environmental issues, where we gardeners can do very little to make a difference, in this case there are steps we can all take in our own gardens to help. Probably the most important one is to stop using harmful pesticides in our gardens, especially the neonicotinoid-based ones such as Confidor, which are absorbed through the whole plant and can poison any insect that visits its flowers. Many retailers have withdrawn them from sale in Australia, which is very commendable. It's a big step to use no pesticides at all, not even the organic ones such as horticultural oils, and I don't know if I can give these up just yet, but I am working on myself with this! Another constructive step we can contemplate taking is to eat more of organically produced food, supporting farmers who are eschewing dangerous chemicals (or grow our own without the use of harmful pesticides).

Orlaya grandiflora with rose Betty Prior, in the former garden of Sandra Wilson in Sydney

Orlaya grandiflora with rose Betty Prior, in the former garden of Sandra Wilson in Sydney

We can also include in our gardens a diversity of flowering plants to attract insects in their search for food. Plants with single flowers (as opposed to hybridised double flowers) are preferred, and many insects are particularly drawn to the tiny flowers of the Apiaceae and Asteraceae families of plants. Plants such as Queen Anne's lace and Orlaya (both in full bloom at the moment!), along with herbs such as parsley, coriander and chervil allowed to go to flower, are some of the Apiaceae plants. The Asteraceae family includes all the many and varied daisy plants, such as Calendula, Erigeron, Echinacea and Leucanthemum species. Plants from the broad Lamiaceae family also seem to be particularly favoured, and these include herbs such as thyme, oregano, basil and mint, which attract insects when in flower, as well as the huge Salvia genus, including the herb sage (Salvia officinalis).

Butterfly on lavender

Butterfly on lavender

Bees like the minute central flowers of lacecap Hydrangeas and Hydrangea aspera Villosa Group (pictured earlier in the blog). Butterflies are particularly drawn to Buddleja species, heliotrope, lavender, Nepeta species and Verbena bonariensis. However, all flowering plants have their insect pollinators, especially our native flora, and it is also helpful to have a variety of plants in bloom in the garden throughout the year to attract them. Another good reason for us gardeners to acquire more plants!

Insect hotel

Insect hotel

Providing a water source for insects is also important, even if it is just a shallow dish somewhere in the garden. Providing shelter and habitat for insect species can be done with one of the cute insect 'hotels' that can be bought these days, or you can make your own out of lengths of bamboo and other hollow material. Another idea, practised at Retford Park garden in Bowral, is the 'tree necklace': an attractive woven circle of prunings, pieces of bark and other natural material found in the garden, placed at the base of a tree, which traps leaf litter and also protect the trees from damage from whipper snippers and lawn mowers. The necklace provides a home for insects and eventually breaks down through the action of fungi, soil bacteria and the action of soil-dwelling invertebrates. Allowing a few weeds here and there is another idea, as these may be a source of food for certain insects; or even a 'wild' area somewhere out of the way in your garden. This can be my justification for weedy areas in my garden in future!

Another thing that gardeners can do is to take on the role of being a 'citizen scientist' and help document the numbers of insects in your vicinity, to help scientists get a more accurate picture of what is happening. One such program coming up soon is the Wild Pollinator Count, which focuses on native insects, including bees, butterflies, wasps, flies, moths, beetles, thrips and ants, to help gain information on the ecology these insects, what flowers they pollinate, and where they are found. Counting wild pollinators on a flowering plant in your local environment for just 10 minutes during the time of the survey can help build a database on their activity. The date for the count is 14-21 November 2021.