Companion Planting: Attracting Beneficial Insects
This article focuses on how you can create more balance in your garden by including various flowering plants to attract beneficial insects which will prevent pest insects getting out of hand.
As we are in the height of the planting season, now is the time to incorporate flowers into your planting plan! It will take several weeks for some varieties to actually flower, so time to get them in the ground now!
A Natural Garden?
A garden is very much a human-made thing! And we, being humans, like to maximize the return on our work. So we focus on the crops we want to grow, excluding not only “weeds” but non-food crops such as flowers. We then create a rather unbalanced ecosystem in which a few varieties of plant dominate. On a much bigger scale, this is the unbalanced, industrialised approach to food production, which has of course led to dependence on pesticides, fungicides and nuking of the soil in an attempt to control the problems we have created!
But nature can show us the way. In a healthy ecosystem, biodiversity is key. The wider the range of species, the more services are rendered and the more networks connect below the soil to create a self-supporting community of plants, insects, birds, mammals, fungi, bacteria, worms etc etc. Such a community is more able to withstand stresses from the environment, and there are more checks and balances to prevent pests and diseases getting out of hand.
The basic idea of companion planting with flowers is that most insects need, just as we do, sources of both energy-rich carbohydrates and protein. Flowers are their providers: producing nectar- the energy source and pollen- the protein needed for egg production and growth.
“Beneficial” insects eat or parasitise other insects, their larvae or their eggs, but adult parasitic insects usually rely on flowers for nourishment. For instance, parasitic wasps lay their eggs in aphids, the young larva develops inside the aphid using the aphid body for nourishment, and then hatches leaving an aphid mummy. The adult wasp, however, gets its nourishment from flowers.
“Pest” insects mostly gain their nutrition by sucking or chewing on our crops, sometimes exclusively feeding off them, and in doing so, often spread diseases.
Both are doing what they should do! The thing is the pests will get the upper hand if the beneficials are not there.
Beneficial insects include:
Ladybirds (both adults and larvae),
Lacewings (their larvae eat aphids),
Parasitic wasps and flies (most of which are tiny and will not harm humans), which lay their eggs inside caterpillars, aphids and eggs of other insects, such as those of the Green Vegetable Bug and psyllids;
Hoverfly larvae
Assassin bugs
Minute pirate bugs
Predatory ground beetles
Honeybees and bumble bees (for pollination rather than pest control)
Useful Insectary Flowers
The most useful flowers to attract beneficials are ones which have florets (eg sunflowers) or tiny flowers, from which these little insects can easily sip on the nectar at the base of the flower:
All members of the daisy family: eg calendula (cool season), French marigolds (summer), zinnias, Coreopsis, cosmos, rudbeckia, sunflowers, yarrow, marguerite, dandelions, puha, artichokes, olearia etc
All members of the carrot family: coriander, parsley, fennel, dill, carrots, parsnips, orlaya, bishops flower, angelica etc
Mallow family: marshmallow, hollyhocks, lavatera, hibiscus, abutilon (these are all edible flowers!), lacebark
Nasturtium
Alyssum
Buckwheat
Phacelia
Flowers for Bees Specifically (bees will also visit all the flowers listed above!)
These flowers are often too deep for the other insects, which don't have a proboscis to send down long flower tubes
Mint Family (for bees): the mint family includes many herbs, including basil, sage, pineapple sage, oregano, thyme, shiso, lemon balm, rosemary, anise hyssop, lavender, bee balm (monarda)
Borage, echium
Gaura (aka beeblossom)
Planting options:
Among: plant the flowers among your veggies if you have the room
Insectary bed/green manure: plant a bed purely as an insectary garden (you will also get lots of flowers for the house!)
Flowering shrubbery of perennials
Make sequential sowings of annuals for a constant feed source
PLEASE AVOID THE FOLLOWING NATURAL INSECTICIDES: THESE ARE BROAD SPECTRUM AND WILL KILL THE BENEFICIALS AS WELL AS THE PESTS!
Pyrethrum
Spinosad (eg Yates Success)
Derris dust
Nicotine
Useful Links:
Our Way of Life Blog: Attracting Beneficial Insects
