Which wasps are worth leaving alone in a South Australian garden

June 9, 2025

Which wasps are worth leaving alone in a South Australian garden

The reflex when a wasp turns up near the beans is to flap at it and then go looking for something to spray, and I understand the reflex because most of us were taught it young, but it's worth knowing what you're actually flapping at. There are thousands of wasp species in Australia and only a small handful are the picnic wreckers. The rest are solitary and not the least bit interested in you, and a fair few of them spend their whole day hunting the exact grubs that are chewing holes in your kale.

The ones doing you a favour

These are the ones you'll most likely see around a backyard on this side of the hills, and none of them is looking for a fight with you.

Paper wasps. They build the open, upside down papery comb under an eave or a branch. They look intimidating and they're one of the better predators of caterpillars and beetle larvae going around.
Parasitic wasps. Often only a couple of millimetres across, so they're easy to miss entirely. They lay their eggs in or on aphids and caterpillars, and the larvae do the rest. If you've ever seen a bloated tan coloured aphid sitting still on a stem, that's one of these at work.
Mud daubers. Solitary and quiet, and far more interested in spiders than in anything you're growing. They're the ones packing mud into a corner of the shed.
Flower wasps. The females are wingless and get carried around by the males, which looks odd the first time you spot it. Their larvae feed on scarab grubs in the soil, so they're working on your lawn beetles for you.

The one that genuinely is a problem

European wasps are established here and they're a different story altogether. They're yellow and black, and they fly in a straight line rather than dangling their legs the way a paper wasp does. They get aggressive around food and drink. They nest in the ground or in a wall cavity and a mature nest isn't something to take on yourself. If you're confident it's a European wasp nest, leave it alone and get a professional in, and it's also worth reporting because the councils track them.

What the useful ones are eating in your patch

Cabbage white caterpillars on the brassicas, looper caterpillars on the silverbeet, aphids on everything soft and new, and scarab grubs down in the lawn. None of that's theory, it's just what a predatory wasp does for a living, and a garden that has some is a garden where the pest numbers never quite get away from you in the first place.

How to bring more of them in

Plant shallow flowers. Adult wasps run on nectar and they can't get into a deep tubular flower, so let a few herbs bolt and flower. Dill and coriander are ideal because they go to flower fast and the flowers are flat and open.
Put water out. A shallow saucer with a few stones in it so nothing drowns. On a hot week that matters more than the flowers do.
Go easy on the spray. A broad spectrum insecticide doesn't know the difference between the aphid and the thing eating the aphid, and the predators are always slower to come back than the pests are. Even the organic ones knock them about.
Leave a corner rough. A bit of bare ground, or an old log you never get around to shifting. That's nesting habitat, and it's the easiest gardening job on the list because it's the one you do by not doing anything.

When to stop being tolerant

None of this means you have to put up with a nest over the back door. A paper wasp nest right where people walk is a reasonable thing to move on, and a European wasp nest is a job for somebody licensed. The point is only that the patch out the back is a different question from the porch, and out the back they're worth having.

Shop related products

D.T. Brown Seeds Dill. Goes to flower quickly and the flat flower heads are exactly what small wasps can feed from.
D.T. Brown Coriander. Same idea, and it bolts so readily that the flowering is barely a decision.
D.T. Brown Seeds Parsley Italian. Let the second year plants run to seed and they'll be covered in small insects.
Brunnings Seed Raising Mix 5L. For starting small herb seed without it drying out on you.

Did you know we also stock a whole bunch of garden gear in the shop that never makes it onto the website. Give us a ring on (08) 8536 4333 to check what's on the shelf.

The rest of the seed and the pest control sits in the garden centre range, and the seed packets are in the DT Brown seed collection.

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Which wasps are worth leaving alone in a South Australian garden