If you’ve ever wandered through a perfectly balanced vegetable patch or a blooming flower border and thought, how does it all just work together so well? There’s a good chance the gardener has been quietly practising companion planting.
This is the art (and a bit of the science) of growing plants next to each other for mutual benefit. Think of it like setting up the perfect dinner party seating plan – keep the chatty, helpful guests next to the quiet ones, and put the troublemakers far apart. In the garden, this means pairing plants that help each other grow better, deter pests, or improve flavour.
Why Companion Planting Works
Pest control – Some plants release scents or chemicals that deter pests from attacking their neighbours.
Attracting pollinators – Flowers draw in bees, butterflies, and hoverflies that help pollinate crops.
Improving soil health – Certain plants fix nitrogen or bring nutrients up from deep in the soil.
Maximising space – Clever combinations mean you can fit more into your garden without overcrowding.
The Best Companion Planting Combinations for UK Gardens
Marigolds and Tomatoes
This is a classic duo, and for good reason. The strong, slightly pungent scent of marigolds is thought to help repel whitefly, aphids, and even certain nematodes that can attack tomato roots.
On top of that, marigolds are brilliant for attracting pollinators and ladybirds – the latter being really beneficial for feeding on aphids. Plant a cheerful row of marigolds around your tomato patch, and you’ll get pest protection with a gorgeous colourful aesthetic. French marigolds are especially good for this in the UK climate.
Basil and Tomatoes
If marigolds are your tomato’s bodyguards, basil is the best friend who makes them taste better. Many gardeners swear that planting basil near tomatoes not only deters pests like whitefly, but also improves the flavour of the fruit.
Carrots and Onions
Carrot root fly can be a nightmare, but planting onions (or leeks) nearby can help mask the scent of the carrots. In return, the strong smell of carrots confuses onion fly, which can damage onion bulbs.
Sweetcorn, Beans and Squash
The American method known as the “Three Sisters” works really in the UK too, especially in warmer summers. Sweetcorn acts as a living support for climbing beans, while the beans fix nitrogen into the soil to feed the sweetcorn. Squash (courgettes, pumpkins etc) sprawls at the base, shading the soil to keep weeds down and moisture in. This needs a bit more space, so it’s perfect for allotments or larger gardens.
Roses and Garlic
Roses may not be vegetables, but they do appreciate a bit of companion planting love. Planting garlic around the base of rose bushes is said to deter aphids and even improve the roses’ scent. Plus, you can harvest the garlic bulbs later in the year, and they’ll store for months.
Nasturtiums and Brassicas
Cabbage white butterflies love laying their eggs on cabbages, kale, and sprouts. Nasturtiums act as a deterrent too, they lure the butterflies away from your veg so they lay eggs there instead. You can then deal with the caterpillars before they spread. Nasturtiums are also edible, with peppery leaves and flowers that make salads look beautiful.
Companion Planting Don’ts
Avoid planting potatoes next to tomatoes – they’re in the same family and can spread blight to each other.
Keep fennel separate – it can inhibit the growth of many plants around it.
Don’t overcrowd companions – they still need space to thrive.
Companion planting isn’t about following a strict rulebook; it’s about creating a balanced, healthy garden where plants naturally support each other. The beauty is that even small changes – like popping a few marigolds in your tomato bed – can make a real difference.
