Companion planting is the low-effort, genius method that will revolutionise the way you plan your garden

When gardening gets a little demanding and stressful, it can be a good idea to find ways to call on nature for a little help. Fortunately, there are more than a couple of ways you can do this.

From picking plants that thrive on neglect to using sustainable garden ideas to keep your garden self-sustaining, there are many steps you can take to make gardening easier. With pests, diseases and stunted growth to work with, it's a great idea to use practices that help you combat these. And that's where companion planting comes in.

So if you're looking for a way to streamline your gardening this year and want a little back-up on the difficulties that come with tending a garden, companion planting is for you.

What is companion planting?

While you might be up to date with current garden trends, some methods easily remain under the radar. Companion planting is one of those methods, but what exactly is it?

"Companion planting is the practice of growing certain plants close together so they support one another. The support can be direct, such as strong scents that make it harder for pests to find a host plant, or indirect, such as flowers that draw in pollinators and beneficial insects that feed on aphids," begins Russell Sharp, Founder of Eutrema.

"It can also be about using space well, with taller crops creating light shade for smaller ones, and ground-covering plants reducing bare soil, moisture loss and weeds," he continues.

Dr Russell Sharp

Dr Russell Sharp is a plant scientist and innovator, best known for developing the range of plant care products offered by his company, Eutrema. He previously served as Senior Lecturer in Horticulture at Moulton College and Northampton University, where he shared his expertise with the next generation of plant enthusiasts.

What are the benefits of companion planting?

Whether you're starting vegetable gardening or want to ensure your flowers last the season, there are many ways companion planting can benefit your plot.

"The main benefits are reduced pest pressure, steadier yields and more resilient growth with fewer interventions," says Russell.

"A mixed planting can make it harder for pests to locate crops, while also supporting predators like hoverflies and parasitic wasps. Flowers and herbs improve pollination in fruiting crops, and fuller soil cover reduces evaporation and suppresses weeds, which is particularly useful in containers that dry quickly," he continues.

Russell points out that in practice, this often means fewer pest flare-ups and less reliance on sprays with a garden that is more stable across the changeable UK weather.

What plants should be planted next to each other?

If you're starting to sort out your garden and want to introduce some companion plants, here is what the experts suggest adding to your plot...

• "Thyme makes an ideal companion plant to roses, as its shallow roots don’t compete with the roses' deeper root system, so they don’t compete for nutrients or moisture. At the same time, the strong scent of thyme will deter some of the pests which love roses, including aphids, blackflies and Japanese beetles," says Lucie Bradley, gardening expert at Easy Garden Irrigation.
• Should you be planting vegetables instead, then Russell recommends carrots alongside onions, leeks or chives. He says that it is a classic combination because the scent profile is confusing to both carrot fly and onion fly, reducing the chance of a concentrated attack.
• "Tomatoes grow well with basil and French marigolds nearby, since basil can help distract some sap-sucking pests and marigolds provide nectar and pollen that keep beneficial insects in the area," adds Russell.

• "Brassicas like cabbage and kale benefit from neighbours such as dill or chamomile, which act as insectary plants, and nasturtiums can be useful nearby as a sacrificial plant that draws aphids away from the crop," continues Russell.
• "Lettuce planted under peas on supports, or near sweetcorn, can sit in dappled shade that slows bolting in warm spells. Strawberries paired with borage tend to see improved pollinator activity, which supports fruit set, and borage also helps fill space without competing heavily at the root zone," he adds.

Unlike other natural pest deterrents, such as garlic spray, companion plants are low effort and won't damage your other plants, especially edible ones.

Lucie Bradley

With over 28 years working in the garden industry, Lucie has been fortunate enough to spend every day speaking to both amateur and professional gardeners. Encouraged to garden since she was old enough to walk, she believes that you can never know everything about gardening, as it is constantly evolving.

What plants can't be planted next to each other?

As with most gardening practices, there are limitations to what you can and can't do. In the same way, there are some plants you shouldn't prune in summer, and there are many plants that shouldn't be planted next to each other.

"Avoid combinations that require regular application of pesticides to one of the partner species. This is because it will be difficult to prevent the pesticide spray from getting onto the other plants. This could mean you get pesticide that was intended for the foliage of, say, a root crop, getting onto the leaves of a plant you eat the foliage of," starts Russell. 

"Alliums such as onions and garlic are best kept away from peas and beans because they can interfere with the beneficial nitrogen-fixing bacteria associated with legumes, which reduces the advantage of growing them. Tomatoes and potatoes are poor neighbours as they share key pests and diseases, particularly blight, so keeping them apart reduces the chance of problems spreading," he adds.

Fennel is also one to avoid, as it can suppress neighbouring growth, whereas mint is such a rapid grower that it can take over space that other plants need. It's technically classed as an invasive plant that could ruin your garden if planted in a bed and not a pot.

What can you plant next to hydrangeas to make them grow better?

As one of the fastest-growing shrubs, hydrangeas are a popular addition to many gardens. But is there a way you can improve their growth and keep them the same for common garden pests?

"Hydrangeas are extremely popular shrubs in gardens as they produce masses of colour through summer to autumn, whilst thriving in our climate. However, hydrangeas can be damaged by a wide range of pests, including aphids, spider mites, Japanese Beetles, snails and slugs," explains Lucie.

"One way in which you can help to reduce this damage is to grow plants alongside your hydrangeas, which will deter these pests. For example, plants with hairy leaves will act as a barrier that slugs and snails won’t want to pass, so you could grow Hardy Geraniums or Lady’s Mantle," she continues. "Whilst you could use the scent of plants such as Nepeta, which thrives in the same growing conditions, helping to deter aphids and attract beneficial insects like lacewings, natural predators to aphids and other pests."

Looking for other ways to keep your garden as low-maintenance as possible? Opting for self-seeding flowers can take away the chore of sowing seeds and will improve your garden's ecosystem at the same time.