I WROTE about how good bugs can help in your garden last week and some of the plants that can attract them.
This week, we're looking at the flip side - how you use plants to repel insects.
Pest repellent plants work in a few different ways.
Masking plants - including sage, sweet marjoram, thyme, lavender, and scented geraniums - produce strong, volatile oils and scents that actually mask the fragrance of the plants the insects might be looking for.
So you can plant these herbs, as well as members of the garlic family, such as chives, near roses and citrus to help repel aphids. They'll also help to keep whitefly away.
There are also repellent plants such as cotton lavender or santolina, tansy and wormwood.
These plants produce a scent or taste that is so bitter or putrid it drives insects away.
Marigolds help to repel nematodes, which is why they are such a good companion for tomatoes.
Oregano will help repel cabbage moth from cabbages, broccoli and kale.
Catnip is said to be good planted with eggplant to repel the metallic flea beetles that chew holes in the leaves.
This herb from the mint family is also a good deterrent for ants, aphids, cockroaches, and weevils. It's also known to repel mice.
Tansy and basil will both repel ants, flies, and mosquitoes, so you might want to plant them near doors, windows and outdoor entertainment areas.
Tansy, lavender, catnip, pennyroyal and mint also repel fleas, so you can plant these near your pet's resting places.
Wormwood is good for repelling cats, and sprinkling the leaves around young seedlings can help to keep snails away.
The scent and flavour of tarragon is disliked by many pests, making tarragon a great herb for intercropping to protect its garden mates. Nearly all vegetables grow well with tarragon.
Bay leaves will help to keep weevils out of containers of dried goods such as flour and rice. You can also place the leaves inside books to deter silverfish.
Place sachets of lavender in the linen closet to help keep moths and silverfish away.
Many Australian native trees contain oils that are effective insect repellents. Eucalyptus and tea tree are among the most powerful.
One of the foremost authorities on this topic is Penny Woodward.
You can order her book, 'Pest Repellent Plants' on her website, pennywoodward.com.au.
The revised and expanded second edition, documents more than 60 pest repellent plants, and has tips on their cultivation and usage.
There is absolutely no doubt you can limit the need for pesticides by including in your garden plants that will attract beneficial insects.
You can also plant to repel some of the pesty ones. It's a fascinating area of study, and there is a wealth of information available.
And it's delightfully easy to make some small changes in your garden that will yield big results.