Companion planting

ARTICLE Anya Kussler 

Of course we all want our gardens to look the part, and choose plant varieties that look good together in terms of their colour, shape and texture. That said, function is just important as form and grouping specific plants together – a common practice in organic gardening known as companion planting – has a number of practical benefits.

The first is that it physically boosts the growth of certain flowers, veggies and herbs. Marigold and tomatoes, for one, are great mates and will flourish when grown alongside each other. That said, pairing up could also stunt the growth of some plants. Sunflowers and beans, for example, are more foe than friend, as they’re both competing for light and space. 

Secondly, companion plants can help attract beneficial insects like bees that encourage pollination and also prevent nasty bugs and pests from feasting on your crops before you do! They contain volatile oils that deter destructive insects, and some of them also attract good bugs to one plant, which then kill any bugs that attack their companion. Some plants also have ‘camouflage-like’ shapes that make it hard for pests to identify them.

Another important function of companion plants is that they interact spacially in each other’s favour. So tall, sun-loving plants, for example, like to share their space with lower-growing, shade-tolerant species, thereby maximising the growth area for all parties.

So let’s have a look at the plants that are set to make ‘besties’ in your garden…

Flowers

• Bee magic. As mentioned, many flowers attract insects for pollination when grown near vegetables, such as the small-flowered capsicums and eggplants. Bee-friendly flowers include calendula, borage, clover, Echinacea, marigold, nasturtium, poppies, purple tansy and sunflowers.
• Foxgloves stimulate growth of all the plants in their vicinity, strengthen delicate plants and are believed to keep your garden disease free.
• Marigolds. The pretty yellow-orange flowers of this sunflower relative make stunning eye candy in any garden, but they also work wonders in waging war on crops that are prone to attack from plant lice, greenfly and twitch grass. Marigolds emit a scent that attracts hoverflies, which feed on plant lice, and their roots produce a substance that keeps eelworm at bay and is therefore ideal for growing near tomatoes, potatoes and roses. 
• Nasturtium. The orange-petalled variety of this edible flower attracts caterpillars, plant lice and whitefly, and will keep veggies such as lettuces, beans, tomato, radish, cucumber and cabbage out of harms way. Yellow nasturtiums have the opposite effect – they attract beneficial insects, such as bees and beetles, and so are best planted away from your garden. 

Handy hint: Planting flowers in a potassium-rich planting mix will boost the growth of their petals, while Acadian seaweed can be added to strengthen the roots and other parts of the plant. It’s also a good idea to feed the plants a slow-release fertiliser that gradually releases nitrogen in order to keep the flowers in bloom.

Herbs

• Basil. This fragrant herb enhances the flavour of tomatoes – both in cooking and the growth process. Planted as a border to tomatoes they attract bees, help deter flies, fruit flies, mosquitoes and plant lice, as well as prevent disease like mildew.  
• Chamomile encourages other plants, especially mint, to increase their essential oil component, making them more potent and flavoursome. Planting this pretty herb next to fragile plants will help revive them, and they will trigger the breakdown of plant matter in your compost heap, too.  
• Lavender. Its delicious taste and fragrance aside, planted as a border in the garden, lavender also makes a fantastic insect repellent and attracts bees at the same time. 
• Rosemary. Beautiful grown as a hedge, rosemary pairs up well with beans, carrots, cabbage and sage. It repels bean beetles, carrot flies and cabbage moths, whilst also enhancing the flavour of these veggies. One vegetable rosemary doesn’t complement is the potato (except when roasted!) so keep them well apart. 
• Tansy. Another great insect repellent that protects against Japanese beetle, cut worms, cabbage words, ants, flies and fruit moths, tansy goes well with cabbages, roses, raspberries and grapes. It also infuses the soil with potassium – to the advantage of any plants nearby. 

Handy hint: Plant herbs in a free-draining, nitrogen-rich planting mix – this will encourage green, leafy growth and an ongoing crop.

Vegetables

• Broccoli thrives when planted next to dill and rosemary.
• Carrots and leeks grow well together – both have strong scents that repel each other’s pests.
• Garlic planted among a bed of roses will help deter plant lice.
• Tomatoes. In addition to basil, this fruit makes an ideal match for asparagus, carrots, celery, parsley, chives and onion.

Handy hint: Plant your companion plants at the same time as your fruit and vegetables in order to prevent insects from going rampant in your garden.

You might also want to read about How to care for indoor plants. 

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*All information is believed to be true at time of publishing and is subject to change.